ALTGR+key is not handled well in vim

[bodzebod]

Hi, I'm using an AZERTY keyboard, and in order to write the character "\", I must use a combination of ALTGR+8 (just an example here, the problem seems to include all ALT characters indeed). ALTGR key is the equivalent of CTRL+ALT, but located on the right side of the keyboard spacebar. When opening an SSH session to Amazon linux 2023, I can successfully use ALTGR+8 key and get "\". However, if I do the same in vim, it gives: <9c> .`I have the same problem when using CTRL+ALT instead of ALTGR. I saw lots of issues reported for vim, looks like there's a big problem with it.