Have a look at my devices in my sig below. I also had a iPhone 14 pro since they were released, I had it for two weeks when I got the S23 Ultra. I sold the iPhone and the two Apple Watches I had (Series 8 and Ultra). The only problem you will have is that it doesn't work with Apple Watch, I haven't had a Samsung watch but have had a Garmin Fenix 7, I gave it to my daughter when I got my Apple Watches (That, in my opinion was a big mistake). I will get a Garmin Epix 2 which is basically the same as the Fenix with a much better screen. That scratches that itch.
Most other things I use on my Mac Book Air and iPads I use Google, Calendar, G Mail etc, so that all works seamlessly. I use WhatsApp which works perfectly, iMessage, blue bubbles or green doesn't bother me in the least, the rest of my family have iPhone and we can still communicate on messages, What's app etc (who would have thought that).
If I am honest, the only app that I find that doesn't work as well with the S23 as with the iPhone is one password but that is still very easy to use.
I find that the S23 Ultra is better than the iPhone in every way (Not withstanding1 password).
Look, here's the thing, I am 65 years old, have the patience of a gnat, am not technically gifted and do not like change. Give the S23 Ultra at least a week, two's better and don't think that it does things worse than the iPhone, it doesn't, it just does them different. I had a iPhone 14 pro and a 13 pro max before it so it was a change. There's even a proper back button on the S23 that stays in the same place, trust me, how good is that. I shake my head when I read all the responses from the technically gifted people who can't use an Android with Apple laptops and iPads, they should be ashamed that they can't figure it out, they will use words such as Bloat and lag because they heard them 5 or 10 years ago, it just shows they haven't ever used a flagship Samsung because those words just are not relevant.
I don't use my iPads any more, this phone is that good and so much more fun to use.