I keep buying different cases, but in the end I find the original Samsung cases the best, especially the leather one.
I've tried many cases in the past, particularly in the context of since Samsung changed their camera design so that the phone rocks quite obviously when placed on its back (?since S21 Ultra). The vast majority of cases have either been too bulky for my liking, still rocks the phone when placed on its back, and/or not grippy enough.
I settled on the Latercase for my S21 Ultra, as I really liked the slimness (basically unbeatable - you literally can't get it much thinner/lighter than that case) on an already relatively bulky/heavy phone. However, it was far from perfect - due to being so thin/light, the case can't prevent the rocking when placed on its back. Secondly, protection is very minimal, so it makes you somewhat nervous placing the phone down any where in any way!
I literally got the Samsung leather case (black) for free with my S23 Ultra - I would get any case for free regardless, so I simply ordered the more/most expensive Samsung case I could find that I might actually like. I was pleasantly surprised how good the case has been, and had forgotten what it's like not having the phone rock at all on its back. It's definitely bulkier than the Latercase, but still slim enough not to affect things in any negative way for me in everyday use (for example, I can still use the phone one-handed easily enough, including texting/messaging, I guess thanks to having relatively large hands, and it fits/slides in my pocket easily enough etc). I also forgot how nice it is to have a slightly more "protected feeling" compared to ultra-minimalist design of the Latercase.
Taking off the leather case is indeed difficult, but actually gets easier after several times doing it (it's actually similarly difficult to taking off the Latercase, and there's a method to do it so it's quite easy actually). I've also been pleasantly surprised by how grippy the case can get, especially when hands are not completely dry/cold. I actually think the grip is getting better with time as the leather slowly wears. I haven't noticed any issues with discolouration that some people are reporting, but perhaps because I have the black case. I'd suggest to those people to try firmly cleaning those areas and see if the discolouration is actually due to some "staining" effect.
In summary, I'm not sure if a case can get much better than the Samsung leather case in terms of being as thin as possible AND having absolutely no rocking on a flat surface.
The only aspect I don't like about the leather case so far is how the 3x camera is completely surrounded by the case - this is obviously a good thing in terms of protection, but is actually a bad thing in terms of increased dust collection rate. I had the same issue with the Latercase, and basically any case design like that (seems to be quite popular now) will have this issue. Probably the most optimal way to reduce the dust collection rate (while still maintaining a good degree of 3x camera lens protection) in this context is to have the 3x camera part "open" with the Flash LED and Laser AF, which I think many cases from Spigen have.