After a few days the focal xfce gave me the blank display bug as well
I have tried now extensively tested two other DE's: gnome and Cinnamon.
Gnome: found that the bug is totally not existant on Gnome (3.36), have run it for a week or so without any burp. Only ting I dislike is that is a bit heavy feeling, not a ssmooth running as XFCE or Cinnamon
Cinnamon: the bug does happen here sometimes, BUT it only takes a 1-2 second until it shows the screen again WITH the chosen resolution. Can live with that as it's a smooth experience and has lot of handy features.
Budgie: I haven't tested it because it is not as feature rich as other DE's in my opinion
BTW hirsute works fine, it's really the Panfrost driver that causes the issue and the DE that copes with it smartly or not
BTW2 i recommend using the oibaf/graphics-drivers ppa for the newest drivers, they do have less bugginess
BTW3 In case your system does bug to a lower resolution everytime if have found you can try setting the default resolution by setting it in /etc/X11/xorg.conf by copying a mode from cvt:
cvt 1920 1080 60 # specify your width height of resolution and refresh rate (60Hz = usually ok)
then copy the output, and paste it into the second last line in the following text blob inside a text editor, then copy all this into the bottom of /etc/X11/xorg.conf (open it in a text editor f.e. sudo gedit /etc/X11/xorg.conf )
Modeline XXX # replace this line here with cvt output