Nextcloud App (IOS/ANDROID) very slow

Hi, we have installed Nextcloud 15.0.8 and the Android (And IOS) latest app in our devices, but when we open and enter into a folder, it takes 6-15 seconds to load the files or folders inside.

I think this is not a good load time, so I need some help for try to identify what is happening here.

We had the same installation with a SQLITE before and was faster than now with a MYSQL DB (We upgrade 2 weeks ago from SQLITE to MYSQL for get a better perfomance, SQLITE get locked multiple times per day when we growth the number of users)

Thanks for your help !

Please I need help with this…

Someone knows what happen?