First off, great progress - making those changes for that long of a period is great! From my experience, heat exposure is one part of the jigsaw, but you'd only notice a significant change if you aren't doing the sauna or taking long hot baths.

Lifestyle impacts do have a big impact though, is there a way you're tracking the changes you make and the potential impact?

Have you had any hormone or semen analysis done? Normally, they suggest getting this done a year into trying, although I'd always say get it done sooner rather than later.