Yeah, Feedback is imo a great issue…
I have these problems, too (I am developing for about 1 year now).
Open posts on reddit, Forums or other platforms doesn’t work as long as it’s not a big AAA title.
Very few people respond or even try it out (and I understand that, since there are thousands of games for ~1$ out there).
I search for testers in the forums I am around.
Look if they “fit”, if they like the type of game and then write a short private message to them.
This worked pretty well up to now, but it is a big efford!
I also thought about a paid job offer “LFW Game testing”, but I haven’t tried it yet.