Having provided IT support in one form or another since 1992, I feel your pain, brother. 👊
Thing is, it doesn't take much to get to a certain level, and the grief and friction (and cost in terms of wasted time!) it saves far outweighs the investment in a a bit of training/mentoring...
I used to teach basic computer literacy for adults in the late 90s - just as folk were getting online at home more. And the stuff we covered then would probably nail the issues you describe... 😆
From my experience, we've gone from offering basic familiarisation lessons to assuming everyone knows how to use a computer. For example, when someone says they don't own a mobile phone, how shocked are you? "You don't own a mobile? But, but, how do you manage?" 🤣