I don't know if there's blooming, I haven't noticed that in normal usage, even in webpages with white fonts and black background. But I noticed that there is 0 backlight bleed on the screen of my MBP Pro 14 that I received yesterday.
For me, backlight bleed is an issue that forced me to return the prevoius M1 MacBook Pro 13 I had.
Screen looks incredible to my eyes. And HDR content is just amazing.