User-719153870 posted
Hi fatihbarut,
Altgr+M it seems as CTRL+ALT+M in keyboard short cut
How did you press Altgr in the keyboard? I cannot found this key/icon and when you assign the shortcut, it maybe already used by other like the following:

Which command do you tried to set the shortcuts as ‘CTRL+ALT+M’?
BTW, if your VS already signed with Microsoft account, it will sync those setting through multiple VS versions.
Meanwhile, you can run the VS installer as administrator to repair VS 2019 to test or go to Tools-Import and export settings-Reset all settings to restore the setting, then test this shortcut again.
Best Regard,
Yang Shen