I tested in a clean profile, and everything seems to work now, so the camera 3 issue might be on my main profile's end. edit the camera 3 not working is a known issue: https://forum.scssoft.com/viewtopic.php?f=181&t=220925 and I have fixed it on my main profile by just do some teleporting... so in c...

I've tested that menu won't open during 1,2,4,8 are active.
change 173 line to default like you said, will make 1~8 work as intended except camera 3.
camera 3 does not work, press the key and noting happen, everything else are perfect, 2,4,8 can stay, also can not go to menu when 2,4,8 are active

Thank you for the interesting mod, in the 1.41 official and MUEC v3, camera 1,5,6,7 all work as intended, camera 2 ,3 ,4 ,8 will work only if I hold the 2,3,4,8 key, once I release the key the camera will become camera 1.
is this intended or some errors on my part?