I got answers and engagement from communities that seemed dead on Lemmy due to lack of users. You should just try to ask your questions… One answer that truly helps is already enough usually, you don’t actually need 100 users upvoting the same answer or 12 different answers where only 1 is good. For many things, low engagement is already sufficient.
I’m sorry if this is not what you want to hear, but I’ll give my perspective anyway.
Why do you care about getting “back in your industry/career”? Yeah you did it previously, but is it really what makes you happy?
When you have goals, you always think “once I reach this, everything will be better”. In my experience and with everyone I ever talked with, this was never the lasting case. Reaching some nice goal gave satisfaction for days or sometimes even weeks or months, but never longer. Then it was back to dissatisfaction and another goal.
The common path frequently described out of depression is getting back into the groove of setting goals, following them, not being satisfied, setting another goal, repeat. This is not how I got out of my depression and also not a good life.
I don’t think it’s important that you reach your goal of getting back in your industry or whatever. I think it’s important that you’re fine with not reaching it. I think it’s important to recognize that you can be happy and satisfied right where you are, exactly with what you have.