Honest question, how/why are you incorporated without an accountant you trust? But, if your accountant isn’t available anymore, and you’re looking for a new one… I can’t imagine Upwork is the place to find one. By “reasonable” I assume you mean cheap. When the penalty for not filing or filing incorrectly one of these forms is $10k, not sure I’d be looking for an accountant on Upwork…
I would say you’d be much better off with something like myexpattaxes.com , there are other apps like it, but I’ve been pretty happy with this one. They handle filing of foreign corporations, it costs more, but at least you know they are set up to handle most situations
How do you figure it’ll get cheaper?