The mean surface temperature of Venus is only 464C.
But, with 93x the atmospheric pressure of earth, water boils at around 300C.
So…what is it that makes it difficult to thrive beyond 100C? Is it strictly the temperature, or is it the properties of water at that temperature? If it’s the latter, I wouldn’t be so surprised.
Also keep in mind that photosynthesis was a genetic accident that just happened to work really, really well, and the ability to process sunlight directly into energy was what allowed microorganisms to move away from thermal vents.
That same genetic accident could play out in a different world. Or a different genetic accident that’s more suited to their environment. Or no genetic accident at all, and life never moves past small, very secluded regions.