That’s definitely not normal. The rendering can be a bit slow, but everything else shold be usable. Unless you have a low-range phone. If that is the case, I can recommend Organic Maps, which are much less resource-intensive.

OnlyOffice has a usable client for mobile. And it’s FOSS.

OSM has much better coverage in Europe as more volunteers contibute. I heard it’s not that great in the US.

crypt.ee is a great alternative, which is extremely well designed. Included in the subscribtion is an online document editor for personal notes and documents. Everything fully encrypted of course & works across all platforms.