I have a PS4pro; technically I also already own a PS5 (kid-brother arrangement; not currently in my possession). When he gets his PS6, I'll get my PS5 back... then still keep the PS4 (always been offline: RDR2; GTA5; &c).
If Sony doesn't offer GTA6 on disc, offline: I'll sell the PS5, too. I just got a 5070Ti, so it's probably back to PC-MasterRace I'll go...
Reasons like this [Sony's 2028 disc-stop] are exactly why I won't be purchasing a PS6. At least (in Sony's defense) they're telling us oldtimers about this now, as opposed to on the day of [stopping disc retail sales].
Rockstar has already announced there's no disk for GTA 6, if you buy a physical copy it's just a download code.