If you look at nearly all reviews of handheld gaming PCs that run Windows, the major problem is Windows itself. So with Valve opening up the door to SteamOS Linux for more devices, it seems HP are interested in jumping in too.
I think with your second point, that if SteamOS was being launched with HP as an OEM partner from the start, similar to the way Valve launched the Steam Machines, that it would be a valid worry. But with the Steam Deck being several years old, and HP not even being an original OEM partner with Lenovo just having launched a SteamOS device, that the likelihood of HP fucking things up at this point is incredibly low. Never say never though.
I think with your second point, that if SteamOS was being launched with HP as an OEM partner from the start, similar to the way Valve launched the Steam Machines, that it would be a valid worry. But with the Steam Deck being several years old, and HP not even being an original OEM partner with Lenovo just having launched a SteamOS device, that the likelihood of HP fucking things up at this point is incredibly low. Never say never though.