I cant speak for the performance of all cloud services, but the others i use with Cryptomator including Koofr(webdav) and google drive have worked perfectly with Cryptomator mobile, its an excellent product. I tend to use Cryptomator with these services and completely uninstall the “official apps”
Pcloud is the only one i’ve had problems with. The USA webdav server is incredibly slow, and i don’t think they even support the EU region servers yet.
If you search this forum (or any other cloud discussion forums) for info on pcloud webdav, there’s a lot of issues and very little support. - EDIT : Please see post 13 here, things may have improved. WebDAV URLs of Common Cloud Storage Services
In my use-case scenario, i opt to use cryptomator with pcloud desktop, and host some large vaults there. Data i need to access on my mobile is stored with a different provider which works better with cryptomator mobile. This works for me as i like to seperate “backup” data from “active/on the go” data
I have lifetime crypto with pcloud i got in a bundle deal with a 2tb package. Personally I don’t like it and I don’t trust it.