I have thought about getting a Boox e-ink tablet but currently just read ebooks on my phone. It's hard not to get distracted though with other apps installed.
Not sure how paying for an item online using Zelle is in itself a scam. The scam would only come later if the stranger had requested your bank info, or you reply to a dodgy email, etc, but so far nothing untrustworthy had happened yet? I don't think that was a good question.
You can disable network permissions for individual apps, which means no ads. Those spammy games that have a million ads suddenly are ad-free, no cracks or pirating needed.
I like learning about this stuff too. I'm curious what is the point of encrypting a hard drive if it just automatically decrypts on boot? If someone stole your computer couldn't they could just boot it up and have an unencrypted drive?
There is an ebook which walks through this setup with specific steps: Extreme Privacy: Mobile Devices by Michael Bazzell (not affiliated)