Yep, I regularly switch between three languages, and one is a complex format. No complaints whatsoever.

Heliboard is also an excellent option. The best multilingual keyboard IMO is the highly underrated AnySoftKeyboard. It is built from the ground up, so it is very different from the AOSP Keyboards and can be a little bit of an adjustment. Development also seems dormant.

(FUTO, Heli, Simple, Fossify, GBoard, etc are all built on AOSP. I think Florisboard is also built from the ground up, although it’s not yet feature complete)