Any tips on how to keep a conversation going with people you semi know without interrogating them beyond the usual getting to know you stuff you'd do with strangers?
I don’t find chit chat easy and I agree the ‘mild acquaintance’ when you’re obliged to make conversation is the toughest.
I often go with holidays (not very 2020, but then there’s less call for chit-chat I guess? Even though zoom socials are pretty grim, you don’t have to speak specifically to the people on either side of you) - there’s often common ground and something new to talk about, people often like to talk about where they’ve been or where they want to go.
If you know where they live, asking for advice on good days out/walks near where they live even if you have zero intention of going there. Or hobbies you’re mildly aware they have - ‘my sister is just getting into motorcycle mechanics, I was really keen to ask your advice on the best kit, I want to get her something for Christmas.’
Anything where you are asking someone to talk about themselves I find works quite well.