I think a lot of people also like you waiting to see S25 ultra first before deciding.
S25 series going down google route all in A.I. again, but their A.I. is really got google backing one not just gimmicks.
So it boils down to if you care about added A.I. features which will be the real differentiator between china phones and Samsuck/google moving forward. Phone hardware reaching a point of diminishing returns liao other than camera hardware which still got room to expand.
To be honest, I don't care much about A.I maybe more for productivity. I'm more old school for the way I use my phone and that too only for work.
Every thing today also A.I but for me, I value a good click and shoot camera, good speakers and a polished U.I reliable for banking apps and security. Security updates should at least be competent enough for basic security and safety.
To be honest, the S25 Ultra doesn't really offer an upgrade in battery technology and cameras. Everything seems to be software restricted in terms of models through OneUI. A.I could possibly be more at a hardware level on S25 Ultra but by and large, S23 to S25 looks and feel largely the same phone. And the bloat on OneUI also contributes to the drain on battery life. And the OnePlus 13 seems to be a good fit without risking any compromises. The biggest plus for me is the battery life and GSMArena just posted their review. Really impressive.
Only thing I'll miss about the Samsung is some good apps like Samsung Email but I can live with another client. The S25 Ultra may offer a higher trade in value for existing Samsung users, but I can't help but think it's largely going to be the same experience since each Samsung flagship phone since S23 really haven't improved main stuff like battery and cameras. It's getting tiring honestly.