It is hard to find modern references on this. When I led a search group, coming from an ML but non search background, I found the following most useful

1. Query understanding series: https://queryunderstanding.com/query-understanding-8a2b16024... 2. Deep learning for search in manning. It covers some non DL techniques

Then it is mostly papers and talking to people. Berlin buzzword has videos of all talks and is very non academic but technical.