I am not saying @thomas-piechocki has no problems, but I have to say I am overall satisfied+ regarding MRA Navigation App. I rode Scotland with it on a €60 6,25" Wireless AA display from our Chinese friends. And Yes: every sometimes connection is lost. I thought I could reduce that to having a less good GPS signal, resulting in a position calculation error, which resulted in restart of the communication: BT connect, WiFi connect and on it goes; automaticly. Sometimes 5 times aday sometimes ten. This reaction might be dependent of the used AA display. Other improvement point, which is far more anoying, is the behaviour wg\hen you come to a standstill. suddenly the screen starts rotating, preferably in the opposite direction from where you came. If you have a bad direction-antenna like me, you are constantly turning arround because MRA tells you so. Look fairly simple to solve using the speed: under 5 kmh, no updates needed. edit: Meanwhile noticed: the "Map Spinning" issue.
For @thomas-piechocki: I use a S25 android phone with offline navigation as much as I can. This saves a lot battery and data. My phone is in the tankbag and is connected to a powerbank: always a stable supply. Hope this helps you a bit.