Have you tried reinstalling win11 ?
I know , that seems to be the standard m$ answer to fix anything.
But, in one case (once in a lifetime) that actually helped/fixed something for me in the past!
But that black thingy you have.. i have had that too an long time..
AND ONLY when Google Chrome wos running !!
does it happen when watching video's/tubes ? That's exactly when it happend to me .. black screen but pc / os keeps running.. and give it some time, after allots of minutes screen turns back on..
I suspect and smell gpu driver + browser conflict there !!
cheers
MOBO : ASUS TUF GAMING X570-PLUS (WI-FI) / CPU: R9 5900x /GPU: 7800XT → RTX 4070Ti / RAM: 32GB DDR4 3600Mhz XMP/ SSD: Nvme ssd Pcie 4.0 / PSU: 850 Watt