Well, my TO (NAS configuration with 2GB RAM) was replaced couple weeks ago by Synology RT2600AC + RPI4 (for gadgets 
) and now I’m completely happy, everything is working , updates on synology are doing very well, if something on RPI4 is going badly then I still have an access to it, because router is alive
Im going to do same thing with my MOX (1GB configuration) which I have in different country, because it is very unstable and I have to unplug it every couple of hours from the power supply, because network is not responding (it was doing before factory reset and its doing after factory reset) .
to be honest I’m very disappointed with that devices and now I will have two (TO NAS + MOX) expensive bricks in my cupboard :-/