I'd definitely try CalyxOS first, as it'll be the closer experience to what you've had in GOS. There's also DivestOS as well, but you're gonna be more limited there since it won't have MicroG (be default, not sure if it can be added in?) So it won't have any real access to play store apps. You'll probably get another 2-3 years out of CalyxOS on your pixel 5 if I had to guess. All depends on how long they can keep the security updates going for it.

LineageOS is a fantastic option, and eventually even when CalyxOS stops getting updates, LOS is absolutely a good choice to continue in using your device for long after the official support window. Just make sure you go with the version with MicroG so Play store apps mostly work as they should.