Yeah, I won't trust Google on that unless they actually deliver. Too many canned projects by that company.
The iPhone 6S got iOS 9 to iOS 15, so 7 years of mainline software support and as of now it's still getting security updates - 9 years later (latest version as of now is 15.8.3 released end of July this year). The iPhone XS entered year 7 of mainline software support with iOS 18.
Sure, some phones only got 6 years of mainline software support, namely the iPhone 7 or iPhone X. They're all still receiving security updates though.
Google just now promised to more or less match that starting with the Pixel 8 series, but they didn't retroactively apply that policy to their previous devices. The Pixel 8 now has just shy of 6 years of mainline software support to go to fulfill Google's promise and we'll see how long they'll release security updates after that.
Just to clarify, do you want multiple remote users connecting to the same desktop session or to separate desktop sessions on the same computer (like a terminal server)?