going back to what OP said and this is my thoughts as I have actual experience with this:
This is often not a technical problem.
What I have done in some cases is used GrapheneOS with just the necessary and minimum things that person needs. Suggesting 100 other different tools is not necessary and will often complicate things particularly for the elderly.
Why GrapheneOS? Well it’s reasonably secure, but the main reason is I can reduce the clutter on that person’s device to just the few related things they need.
A lot of these scams are phone call related, and that requires education, eg nobody is gonna call you and ask for X, Y, Z, A, B C.
The less stuff you give an old person to worry about, the more likely they will identify scam/malicious activity. The reason for this is because things out of the ordinary that are not what they are used to will “stick out”.
Just know any decisions you make, you’ll have to support.
And yes, suggesting random Linux distributions like mint is not helpful. Not only is Mint nothing like current day operating systems it’s not secure in any way special.
If I was choosing a desktop distribution for aged person I would pick something probably GNOME based because it is most similar to their phone. Also GNOME tends to have better QA and testing/and resources than Cinnamon ever will. Failing that I’d select KDE, which again is about the same in terms of testing and QA as GNOME. Yes people don’t work for free so a funded community GNOME/KDE is always going to have more developers and vibrant community.
Likewise country avoidance is not going to help here either to address any of the concerns that OP mentioned.
If you do use uBlock, you’re going to want to use it in easy mode, and probably follow the recommended instructions we provide on the site, ETP strict etc.
The other recommendation would get them to use a password manager. In some cases like this the aged people I set this up for (in their 70s) were still running a business and shared data with their son, so we used 1Password as it had a clean UI, very good on Apple devices as well. While I like Bitwarden myself, I wasn’t as happy using that on their iPad, iPhones etc.
If you’re setting up a windows machine, no reason that windows defender isn’t sufficient. If you look at testing you’ll see that it is about as good. Once again a lot of modern day virus scanners are basically nagware because they want to look like they are doing something.
TLDR:
- old pc = fedora workstation gnome/kde
- newish pc (as in capable of windows 11) = leave it with windows on there
- mac okay leave it as mac