Oh wow, looks like I started writing my own post re: bad muting experience at almost the same time as you posted yours.
I totally agree that the way muting is implemented in latest fw (2.11.1) it’s not practical at all.
I’m not sure I could easily see truly one-click implementation of muting working fine in 2x2 and 6x6 modes, however I see a couple things we could make to improve the situation dramatically, I elaborated there Proposal to improve track-muting experience
Do you think it could help in your case?