Here are some advices, I have found the same.
Rule number 1 in getting your stuff tested (this is just a general design rule) - you get feedback on the stuff that you show. If you show stuff that is highly artistic, then you will get feedback on that. So if you only want to get feedback on gameplay, try removing distractions in your documents or make sure that the focus is on the stuff that you want tested.
I have found great success in testing peoples games, and asking them to return the favor, and making posts here and on reddit, where I exchange a "test for a test" .. I test your game, if you test mine. This gives me an enourmous amount of value, and help me a lot.
If you could leave a link to your games here, then I could test them ;)
I also go to play sessions in Copenhagen.. and if you live in a bigger town, there would probably be something similar going on there.
I have a podcast about Design - recently I made an episode on Prototyping which might have some hints in it https://www.hiddenbydesign.net/2024/12/31/s2e30-prototyping/
Lastly, practice giving and recieving feedback - this is a more difficult skill than you would imagine I also made an episode on that https://www.hiddenbydesign.net/2023/11/29/s2e7-how-to-feedback/