Thank you.
Probably this is one of the reasons for poor perfomance of n64 in pi4.
And dreamcast have the same problem with the videomode.
Would be interesting for testing, that someone with a pi4 or rpi400 do the videomode change test with n64 and dreamcast to see if it works, checking always the final resolution in tv or monitor, and if works post the options used.
Hopefully the new version will be soon.