I’ve been using iPhone 14 Pro Max for a year which my company gave me. But it has disadvantages more than advantages for me. I want to change it with an Android phone that bootloader unlockable. I want to install Google-free ROM.
A little note, I don’t like S23 Ultra in particular because I really don’t like its frame.
The Pixel 8 Pro is likely the best. You can flash graphine or pretty much any rom. Samsung really doesn't have custom roms anymore. If you get a pixel buy it from the Google Store
The reason is locked bootloader's, some carriers lock the pixels bootloader down meaning you can't install custom roms. Some lock it until the device is paid off or during a 90 day period.
Also take a look at the Pixel 8. In my opinion the 300 euro premium for the 8 pro is not worth:
12GB ram instead of 8
A temperature sensor
Telelens
If you realy prefer a bigger phone, go for it. But I think the Pixel 8 is a better deal if you want to go for a custom rom like GrapheneOS, because you mostly pay for extra software features with the pro, that you can't use with a custom rom.