T-665 excruciatingly slow (and buggy)

So in general I am happy with my T-665, especially with the build quality. But the more I use it, the more annoyed I am with a couple of things.

First: It’s SOOO f*cking slow. I switched over from my Garmin Montana700 to this, partly because I just couldn’t stand a map that had to reload after every zoom, yet here I am again, waiting like I’m using the TomTom in my old Volvo from 2001. Offline navigation (e.g. in OsmAnd or directly in DMD2) for a route that’s about 100km long takes about 1-2 minutes minimum, compared to 3-5 seconds on my iPhone 14. Is all this just normal and do I have to accept that or is there any way to speed this up? Would this have been different with the T-865? Would it be different with actual high end smartphones (but then, what does the “OctaCore” of the T-665 actually do all this time?)

And second: DMD2 seems to crash in the background, a lot. When switching apps, it happens multiple times a day, that the screen just goes black when I want to switch back to DMD2 and there’s no way to restart anything at all. I can access the control center by swiping down from the top but that’s about it. I have to force-restart the phone then and often have to wait again while it’s taking its time to do the offline navigation calculation…

I re-installed all apps, have installed all available updates for DMD2 and I have no idea what else to try. Or is all this just to be accepted?