Based on this added info I think it would be a major improvement. So I'd say go for it!
BioMyth
Honestly it largely depends on your main PC specs, but like you are hearing from others. It probably isn't a good idea.
It is the largest reason. Storing the password is one thing but to make the device reasonable to use I would likely store the key's in TPM with a backup key. I don't think she would be technical enough to use the backup keys were something additional to happen.
BioMyth
I understand that giving the keys can partially solve the access problem. But she would still possibly be unable to use the device. Additionally, I don't know that she would be capable of using the keys without additional assistance and we don't have other techies in our community who could step up in that capacity.
I don't for a pretty simple reason. I have a wife, if something ever happened to me then she could end up a creek without a paddle. So by not having it encrypted then, anyone kinda technical can just pull data off the drive.
In the sand
So many times I've been on a great streak and I just can't sleep right anymore and it ruins it all.
Also apparently cron works in termux, so it could all probably be scripted there.
I think you could get something working using termux to install and run ffmpeg on your phone. Then using an automation app, e.g. if this then that, you could run a script in termux to re-encode the files. And automate it at night while charging.
Using the dictionary definition of a term like sanitary when applying it to an industry with its own specific definition, food prep, makes your argument seem like it is a bad faith argument. I don't think that is your intent here, I just want to bring to your attention that your point will be missed if you use a term with multiple contextual meanings in & out of industry since it makes the argument linguistic rather than point by point.
As someone in a similar environment, there are others who care. It just isn't worth the risk to my job & professional relationships to talk about. Most people who don't care I won't sway anyways and anyone who does care doesn't need to talk to me. So, for the betterment of my family, I stay quiet at work. Outside of work though I'll talk to my friends & anyone who will listen about the risks of the current regime.