I went to Insomnia in Berlin once and had a great time. It really depends though on the night you go and who is there.
I met several friendly people and of course had some fun. Additionally, talked to the lady that runs the place.
What I did like was that it is not far from the Ubahn, so you can get there easily. Unlike swinger clubs in NRW which are usually situated outside of the city limits.
Now, I can not say ho Corona will have an impact on who goes to parties and who does not. All I can say is try it. If you have fun great.
Just make sure you get a test or whatever they require.