Nixon certainly didn't help, that's when Republicans really ramped up stoking discord for political gain. Our decision to get involved and then dig ever deeper into the Vietnam shit sandwich derailed so much potential social progress.
Look up the exact model of the phone then check GSMArena or a similar site to see which bands it supports - then check to see which bands your carrier requires.
Also, in the US I usually recommend eBay or swappa for phones - their buyer protections are robust and it's almost trivial to return the phone if there's an issue that isn't disclosed in the sale listing. Buying used/refurbed things on Amazon is a crapshoot in my experience.
I moved my elderly mother to ChromeOS and I no longer have to deal with the IT burden of supporting whatever she installed or broke this week. Move your parents to Linux if you truly enjoy being an on call unpaid helpdesk
I've had the idea for a while to use an LLM to gather metadata about books for me as well as generate tag lists for themes, plot, writing style, etc for everything in my ebook library. You could also generate non spoiler plot summaries and produce recommendations for similar books.
I leverage btrfs or ZFS snapshots. I take rolling system level snapshots on a schedule (daily, weekly, monthly and separately before any package upgrades or installs) and user data snapshots every couple of hours. Then I use btrbk to sync those snapshots to an external drive at least once a week. When I have all of my networking gear and home services setup I also sync all of this to storage on my NAS. Any hosts on the network keep rolling snapshots stored on the NAS as well.
Important data also gets shoveled into a B2 bucket and/or Google drive if I need to be able to access it from a phone.
I keep snapshots small by splitting data up into well defined subvolumes, anything that can be reacquired from the cloud (downloads, package caches, steam libraries, movies, music, etc) isn't included in the backup strategy. If I download something and it's hard to find or important I move it out of downloads and into a location that is covered by my backups.