On point 4 - I do think it’s tempting to say “we used to do it this way at my old place, and it was much better”. I call it “at my old place” syndrome.

However, if you never take your learnings from place to place, that’s also pretty useless isn’t it?

I think it’s more about how you communicate those learnings. Perhaps start by not suggesting they are better, just that you’ve also seen it done a different way in the past (I.e. avoid “at my last place...”) and you’re wondering why we do it this way instead. People are going to be much more receptive to not opening with “I know better”, especially because when you do it this way you often find they’ve already tried it the way that your previous place did it and it didn’t work for them for very straightforward reasons.