Installing Linux on PS5 is an exploit as far as I understand it, and requires specific software versions that are already long outdated at this point. But PS5 already runs a Unix like kernel as far as I know. So yes, it would be possible to do it on them if Sony or Microsoft allowed it. Though I doubt they ever will since you could not run Playstation or Xbox games on Linux without huge investment from their side. It’s a solution for those looking to jump without the hardware cost, but I am a little anxious in recommending it since Sony full well considers it still their device. And Nintendo has recently shown they aren’t shy from just bricking banning your device from their services if they think you’re not using it the way they want, I would expect the same from Sony. But if you do it right, probably no way for them to find out. But you could never go back to it just being a Playstation 5 too. In the end it’s essentially the same path as my first proposal.
I also notice that when there is a discussion or video regarding modding a console, it’s to “preserve” its longevity rather than having a practical use.
I think that’s in part because it’s an attempt to tiptoe around the ‘red lines’ of console manufacturers. It’s trying to stay as inoffensive as possible so that it doesn’t get put into the same bag as emulators or third party tools to circumvent DRM.
EDIT: The switch example wasn’t bricked, but it was banned from using the official services, which isn’t much better, but still a distinction to be made.

I hear this more frequently nowadays, but it really is kind of misplacing the blame for this change. Steam went for this model precisely because many of the bigger game companies to this day refuse to sell their games as anything but a heavily restricted license. And Steam as a storefront does have to cater to them in that regard, especially back then. Even physical disks as others pointed out were technically not something you owned, but rather that resale and such was not enforced or enforceable. (You would definitely get some stern letters if you started copying and selling those games at larger scale, even if you ‘owned’ the original copy).
People do still sell DRM free games on Steam that you can copy and distribute to essentially your hearts extent without Steam ever getting involved. The license you have is for Steam to provide you the download service so you can get your digital copy (and a bit more). If you care about people owning games, then it’s up to you to support and buy from the kinds of companies that don’t provide you a license or (more likely) where the license is unrestricted enough to fit your description of ownership. The middleman like Steam you buy it from shouldn’t matter if they don’t exert undue control beyond that. And at least being on PC if you really must buy something with DRM you have options to remove it.