Although I didn't want to start a DSLR vs ML post the replies were very interesting to read!
There is no doubt that currently DSLRs deliver better IQ for the money and are arguably more reliable in many situations. Maybe in the future things will change, who knows.. and as someone pointed out it is not wise to invest serious money in ML at the moment and in my situation especially since it'll be a second body I would use just for fun and lightweight every-day walk around. I'd bring my d810 99% of the times when I travel or when I plan a shoot, thats why I don't really need to have a zoom lens or great AF capabilities, sometimes it's just nice to go out just with your 24 - 28 or 35.
Manfred said focus peaking in ML is as reliable as the AF confirmation and to me that sounds very good, especially because you see it on your subject without having to look at it on the bottom left corner (now of course it is not the best way to focus a manual lens but how many times can you shoot in live-view zoomed in 100%?) there is also a magnification aid you could use directly in the EVF that sounds very nice.
That said the choice seems to go towards the sony APS-C maybe a6000/a6300 with a kit zoom (300-400€) and Ai lenses on the cheap side or maybe a fuji and a 23mm f2 so i keep AF and can adapt Ai lenses anyway but this would be a costly option (around 600-700€ if I'm lucky). Another option could be going on a MFT camera but I'm excluding it since good lenses cost a lot and the crop factor doesn't help at all with my FF lenses (yes there are many cheap vintage, but are they really worth it?).