If you really need a computer and don't have the budget for one that costs $600, then don't get a $600 computer. There are plenty of old office PCs on eBay that you can get for less than $100 and they should be fine for only homework. Just search for "Office PC" on there.
This is not the place to be asking for money, but I hope you find something that fits your budget and that university goes well.
Kind of, you can share individual albums so it is possible to share all but one. This may or may not be practical though depending on your album structure.
My only advice would be to go full NextCloud at first for simplicity instead of trying to integrate it with other services.
That being said, if later on you're looking for a way to store images I'd highly recommend Immich, I just finished setting up my own hosting setup a few days ago and it is gorgeous.
I always take out those paper ads that are attached to the top of the seat if front and turn them around so I'm not staring at them for a 5 hour flight.
Not for polybar but you might like to look into SwayNotificationCenter, I use it as the notification daemon of my hyprland setup and it has all the previous notifications in a menu with a do-not-disturb mode. I use a keybind to open up the menu but you could add an icon to polybar that when clicked runs swaync-client -t to toggle the menu.
In my experience combining multiple languages usually creates more complexity and is slower than each of them individually because you need to convert the data structures of one language into those of another. Both of them are great languages and I've made web services in both so whatever one you pick will be a good choice.
As for which one to pick, although Rust is my favorite language, if you don't know it it'll take a while to learn. So for this project I'd say to go with Go because it's simpler and you really won't notice a performance difference unless you've got a huge amount of traffic.
The only problem is that there's no way to make a recurring payment even if I wanted to, which would be more sustainable than one-time purchases.