I have the Proton Unlimited plan so I’m using all their services. I create a new email alias through Proton Pass, which uses SimpleLogin, for every site I sign up for. If I receive an email through the alias in my Proton Mail inbox, and I reply to it, it goes through the alias and doesn’t expose my true email address.

All very easy to setup and do.

You may find this project useful. https://github.com/justin025/onthespot

Or https://github.com/schlagmichdoch/PairDrop if you don’t want to support a project bought out by LimeWire

I used https://tweetdelete.net/ a few years back. I had to pay for a premium account for a month to do it but it was only a few bucks. I’m not sure what “expensive” would be in your books.

I don’t have any input on your hardware but for software you could look into Ente. They have a self-hosted version.