You can try to setup client logging using sentry or a similar framework.

At this moment I only tried to contact Apple a few weeks ago and got what I'd consider a standard response "we need time, we're looking into it, here's the ticket number". I've read that for some making a new submission works, or even rereleasing an app, but as far as I understand it's a dangerous route that can lead you to get your account blocked. The other options are reject appeal & request for an expedited review, but I don't have much hopes for those to work either. I feel like I'm stuck with no estimation or either understanding that the review will be finished eventually.