TL;DR: From my personal experience, hold out for a week or so and then see whether it has gotten better or not.
I also just upgraded from my trusty S10 only using SwiftKey, to an S24 Ultra now, trying to stick to Samsung's native keyboard for the AI features. I was very skeptical at first, but then later got more and more used to it, to the point where I personally feel like the benefits of the native keyboard actually equal out the negatives. Here's why:
I type in 3 different languages (Danish, English and German, prioritized in that order) on a daily basis, where it's not only important that the keyboard layout of the language I'm typing in matches, but also gives me word suggestions and corrections relevant to the language. Similar to SwiftKey, you could just add more languages to Samsung's keyboard and then swap between them by swiping left/right on the spacebar button. However, it seemed like the prioritization/order of the languages I had added were not being taken seriously by the keyboard, since the default layout would always seem to be German (my least used language) no matter what I did in the settings. So this quickly just got in my way of typing as smoothly as I used to with SwiftKey.
HOWEVER, after a couple of days and a few tweaks, I realized that the phone was just trying to "calibrate" to my habits and actually seems to notice what app I'm typing in and automatically switches over to the language I last used in that specific app! I also feel like it's better at remembering my typing habits, as well as predicting what words I'm about to type and then suggest exactly that.
No clue whether this is due to the built-in AI or not, since I haven't read anywhere that this is the case, but all I can say is that it certainly feels that way.
