The problem is that if you run your own email server at home, you get blocked as a spammer these days. Today, to send emails you MUST use one of the big providers, or your email won't get delivered half of the times. One has no alternative but to use these free services.
I don't like KDE at all. Too busy, terrible-looking right click menu on the desktop (some lines long, some short). It's that stuff that give me OCD. I like cleanliness in the UI.
I'd go with XFce. I have it installed on many old laptops that I have given away to my cousins, nieces, and mom. Works like old Windows if you modify the panels (remove the bottom dock, bring the main panel down), and then you put some sane defaults, like setting up sleep (NOTE: you will need to edit a file to make xfce go to sleep unattended), enabling natural scrolling, enabling the login manager to show username so they don't have to type it every time, etc etc). But after all that is setup once, xfce is the best case for an old laptop.
That's what "ALL Applications" does, it lists all applications. And it's best to have enough apps to start someone up, than to be bare bones. There are categories to easily find what you need. I personally never use the "All Applications" option. I must say again, download Cinnamenu, it's better than the default.
Your model has no GPU, so it's possible that no graphical environment is supported. I suggest you sell it and get a Raspberry Pi if what you're after is a more desktop experience.
Linux Mint works perfectly as far as I'm concerned. I've never seen or heard of the issue you mention where the menu resizes all by itself. Or do you mean that after you switch to 4k it's too small to see? (btw, do you know that you can resize its window using the mouse?)
If you want something larger for a 4k display, simply install the Cinnamenu instead (you can find it from the Applets window, and then download it from there). I have it setup to show large icons instead of a list. It looks absolutely great on my 28" 4k screen. And it's also resizable.
Then, there's the issue of tailscale. Why download it as a flatpak? Why download 1+ GB of data for something that is just 26 MB even when statically linked, directly from the OFFICIAL website? https://tailscale.com/download/linux/static Why use third party uploads for something as critical as a server, where security could be an issue? Just get it directly from the official website.
You will need to find out if that's the B43 or the wl driver and install it from the repos via some method (e.g. usb-to-ethernet). Both Mint and Ubuntu use the same repo, and Ubuntu usually allows some non-free firmwares and drivers in their repos, Fedora doesn't.
So basically you're saying that you would prefer the "recommendation" system, and not the Reverse-Chronological system. You would give up equality and fairness in posting, just so you could conveniently avoid 2 seconds of scrolling to find the posts down the line.
It's the recommendation system that destroyed FB Pages, and Instagram for photographers and artists. Suddenly, the system found they were not worthy of recommending their posts. Careers were lost.
I personally avoid AI recommendation engines like the plague. Lemmy/Reddit's voting system is as far as I go.
The machine is fully supported by Mint, but because it's a non-free firmware driver, you will need to add either an ethernet cable, or a usb-to-ethernet adapter, or you could tether from your phone. Then you can install either the b43, or the wl driver (depends which chipset you have), and then wifi and bluetooth are going to work like a charm. I had to do the same on my mac mini. Apple uses broadcom chips that don't have full open source bits, so they're not part of the live ISO. You'll first need to find another way to get to the internet, and then fetch the right files.
The laws don't go far enough to protect usability of both the hardware and software. For example, the new EU law about software, only requires smart TVs to have software updates for only 5 years (my own $2k Sony TV only gave me software updates for its AndroidTV for only 2 years! -- these days I don't connect it to the internet at all due to security problems). Who throws a TV every 5 years? IMO, it should ask for 6 years for full updated phones, plus 3 additional years for security updates, computers should go to 12 years, and TVs to 15 years.
Personally, I've been gathering old laptops and towers from friends and family and "upgrade" them with Debian and XFce. As long as they have more than 450 Passmark CPU points, and 2+ GB of RAM, these machines can still serve a purpose. So far, I've repurposed 12 such machines and gave them away back to their owner, my mom, my nieces, and two of my cousins. Even on machines with only 2 GB of RAM, it's enough to run a browser with up to 3 tabs before touching the swap file (Debian/XFce clean-boots to about 800 MBs of RAM). That works just fine for someone like my mom who doesn't even how to open a new tab, or for a young kid researching for school.
I would do the same with old phones too, but most of the models bought here in Greece are cheap Chinese Xiaomi/Huawei/realme phones, so LineageOS doesn't support them. That's the biggest travesty these days, since very few people buy computers now. Think if Google could ask as part of android license that all phones have usb-out for monitors, and all these phones can then be transformed like Samsung's desktop DEX OS. I mean, most phones today have 4+ GB of RAM and 128 GB internal memory, just like an old laptop would. It should be able to transform itself into a desktop OS on demand and extend its life and its purpose.
I will tell you my secret. I have two phones. Two identities. One that has a normal google phone with facebook messenger and instagram, to keep in contact with family, and to have bank apps. And one, where the Murena e/OS is totally de-googled. Where you will only find FOSS apps, from Lemmy to Mastodon and Pixelfed. That second identity is my real one.
The mistake people make when they write about "moving to Linux" (or similar), is that they try to fit themselves into a box where the modern life doesn't affords them to. The wiser option is to play on both sides. You have an unassuming, clean-cut identity on one computer and phone, and you have your real self on the other, where it's ultra-private and secured, and often IP-spoofed if required. And it's not some kind of closeting thing, or illegal thing or anything, it's just private. How I would like things to be by default in a Utopian system.
On top of that, I believe that Murena's e/OS has a modified g-services app so full fledged Android apps, including bank apps, get fooled so they run. But I don't personally run them on that phone. That phone is FOSS only.
The problem is that if you run your own email server at home, you get blocked as a spammer these days. Today, to send emails you MUST use one of the big providers, or your email won't get delivered half of the times. One has no alternative but to use these free services.