[recursivecaveat]

The most common interview types to prepare for are the leetcode, systems design, and behavioural. Sounds like you're already working on the 1st, but at least a little time rehearsing the latter 2 will improve your performance there a lot.

In my experience if you've been a paid developer using language or technology X nobody is really going to explicitly question your knowledge of that. So I don't think it's a great use of time to dive deeper there. I would focus on expanding your toolbox and the pool of jobs you can apply for. Languages that are popular and/or you've worked with tangentially in the past. This demonstrates some flexibility and independence too even if you don't land on one of these imo.

Good luck out there!