At the moment i got a router-modem-combination from my ip and i want to be more independent.
Therefore i want to use the provided hardware as bridge and buy my own router to manage my network.
In my home network i got
2 Desktop PCs (cable)
1 Switch (cable)
Several WiFi devices including smart home devices
Pi-Hole
Mac Mini as a linux Server (cable)
Synology NAS (cable)
AVM repeater
Before i start my own extensive research, may you recommend me a Router for my setup?
I personally like mikrotik routers. They have all the features you could wish for and then some and they're relatively cheap for the things they can do. I have RB4011iGS+ (I don't think that exaxt model is available anymore) and it's been rock solid. As I have fiber I just pulled the SPF-module from ISP's box and plugged it in on my own hardware, so the router ISP provided is just gathering dust right now.
But it depends on what you're really after. If you just need basic firewall/NAT/DHCP functionality and your connection speed is below 1Gbit pretty much any router will do. If you have fast connection and/or need for totally separate networks/VLAN/something else it's a whole another matter.
I have an RB5009 and it's great. I'd say they're actually quite easy to get going with the default config. It's when you get the itch to start messing with stuff that the learning ramps up.
Second the RB5009, I have been using it for some time now and love it. It was an upgrade from my old Mikrotik router, because I wanted more performance out of the tunneling. Performance is one thing the RB5009 has in abundance.