The Samsung keyboard is awful, but I'm used to Gboard on Pixels and trying to use an iOS device is a nightmare.
Also, for at least the last ten years all of these keyboards learn from your inputs, the words you use, and how you misspell things. If you switch to a new device, you're starting from scratch on muscle memory, but the device is also starting from scratch on your-input-memory. iOS at least carries over your keyboard data between devices, but that isn't something that syncs between Android devices. (especially not between different manufacturers)