Ingolf you probably read the website part about supported devices, if you read further below, you'll see why nothing else than Pixel phones are currently supported.
GOS is all in on security and privacy and Samsung simply doesn't meet the high standards.
My recommendation: If you really want security, privacy and agency over your information, you'll eventually want to use GOS. Get a cheap compatible Pixel 8a for starters (make sure it's OEM unlockable) if you want to test it first. The devices are not perfect design or performances wise, but they're the best by far regarding security (for Android devices, iPhone hardware is on a similar level).
You can always flash the regular Pixel OS back and sell your 8a later on in case you can't get away from Samsung, but if you're anything like me, you'll never want to look back after experiencing the many features of GOS first hand.