Despite their differences, I can use Quick Assist with both. And between my Dad’s sudden turn towards becoming me in high school and my Mom’s innocent transgressions, I’ve never run into anything I couldn’t fix with it.
Worst case scenario, my Dad and I have talked about a volunteer based group of people who help other cats around his age. If your parents are on the same side of the ocean as we are, we can help in a closer timezone. My Dad is a retired police officer (you can trust him) turned nerd (you maybe shouldn’t trust him) and I’ve been drafted into the odd role of his nerd supervisor. If you’re worried about your folks, he’ll give them his phone number.
I don't have a lot of experience with remote administration, but I use Tailscale with RDP/VNC/SSH to access my own machines when I'm away from them.
I like to avoid TeamViewer/AnyDesk/etc... because the GUI makes it too easy for folk to get scammed (watching Kitboga all these years makes me want to avoid them like the plague).