Hi, with the HDMU team NOT having any AzboxHD anymore, and the main repros not being public, I think you will have to either find your own solutions , or hope for someone else with a Premium(+) to help out.
wifi always has had issues. unlikely this ever to get changed/fixed.
the RTI-Sys plugin could be changed by the team, but not tested.
for the language freezing problem, you really need to provide some more info, like debug log when the freeze happens. (which channels, always or only somtimes, etc...)