but classically, before his death and resurrection, he was a solid herald leveller...he was beaten by Warlock, beaten by Mar-Vell, and beat classic Drax in some brutal, awesome fights. After his resurrection though, all his sub par showings were retconned and he was consistently impressive....until relatively recently.
Darkseid showed he could be flat out beaten by Superman and Orion, and until the last few years, post resurrection, Thanos had no showings where anyone at herald level seemed able to beat him (again, because of the clone retcon).
Now, its not as good for him, and he'll be brought back to a top end herald, where he was pre resurrection.
Yeah, I'm not exactly buying that Thanos shouldn't be able to beat Darkseid. As for whether Thanos "should" be able to withstand BB's voice, well....he did.