I doubt any company who could be a viable candidate to enter the console race would do it.
Google would never get off the ground with a console because they can't be trusted to support anything they make, and considering they closed down their game development studios prior to ending Stadia they don't even have the means to create content for their own platform no matter what form it takes.
Valve made the Steam Machine prior to the Steam Deck, which was their attempt at a console-like PC gaming experience but it sold poorly and was cancelled after three years, so they're not going to try again, especially with Steam Deck performing well for them.
NVidia could have been viable but they were doing the Steam Deck before Valve and as far as I know it didn't do well and died off. They also lack any game studios so like Google, would be unable to support a console with first party titles which are crucial for a console.
Amazon has their own game studios but they've only made two games, and I don't know how well those games have performed commercially but I never see them mentioned anywhere online so I get the impression they're not doing too well; certainly not enough to support a console launch. Considering Amazon doesn't even offer Luna (their cloud gaming service) as an independent service and bundles it in with Prime, and only offers a handful of games on it at a time for a limited period, they don't seem confident in being able to grow their own gaming ecosystem and the lack of attempt to try tells me they never would. They would also need to actually develop more games and have those games be highly acclaimed to even generate interest in a home console, because right now I don't think what Amazon has produced would entice anyone into a console from them.
Sega is likely the most viable of any because they have the studios to support a console with first party games, but I don't think it would be a good look for them to suddenly take all their IP and have them only on their console. I think you'd get some people willing to buy a console to keep playing those games but I feel a majority of people would just opt to not bother, or at least enough to make it hard for a Sega console to be financially successful.