PE Interview Prep: Industry Knowledge

Second year (ignore title) in the process for some firms in off-cycle. Trying to understand how I can best prepare for the investment framework / case study / industry knowledge portions of the interview.

I'm interested in tech opportunities and am curious how many sectors we should have under our belt in terms of solid knowledge. You can obviously do basic research on a bunch of different sectors but dunno how useful that can be so it makes sense to do a deeper dive for a more select group of companies. So, just wondering how people approached this - what is a good number of sectors to be knowledgeable about and within each, how many companies should we know?

And what kinds of companies in what varieties should we know (i guess not necessarily industry specific but in general). Like, say you were interviewing for a tech fund. Should you have 1 public company you know well, 1 private, 1 good buyout opportunity,  good growth investment opportunity. Just trying to understand how deep I need to go in terms of research. Hoping someone experienced can help out, thanks.