No, even if the trapped carbon in the crust were released we’ve had far greater carbon concentrations even more recently than 350m years ago that’s been cited above. So the last time we had really high carbon concentrations in the atmosphere I don’t think the sun has warmed enough in that span of time that a return to those conditions wouldn’t turn us to Venus under any theories I’ve seen put forward by serious researchers.
Venus almost certainly didn’t turn into what it is because of carbon based activities of organic entities on its surface. We all know that major volcanic eruptions here on Earth can have an immense impact on greenhouse gases in the atmosphere, one very big eruption could even surpass annual human production of such gases. I thought one of the most likely theories on what’s happened to Venus is it is much more volcanically active than Earth, with more frequent and more powerful eruptions. Earth would indeed probably turn into something like Venus if it had continuous large volcanic eruptions all the time. Because they keep adding more and more material into the atmosphere. But organically based sources of carbon in the atmosphere probably couldn’t get a planet to such a state because they’d have killed off lots and lots of the planet (and probably themselves) long before that after which the source of production would be gone (and probably have decreased as more and more of the planet died off) and presumably over millions of years the greenhouse gases would leave the atmosphere.
You need something that can’t be wiped out by a feedback cycle like that to turn a planet into a Venus, which means something unconcerned with the surface rising to insane temperatures or the air becoming toxic–and volcanoes are famously unconcerned with either of those things.