Du you want a plastic box or a pc with your own os on it (like opnsense or Linux)? It anything in between? I would say the 2 ends are between a fritzbox and an AliExpress router PC.
Btw throw your repeater away in case you use it as a Wi-Fi extender. It cuts your wifi performance to 1/4. It only works if you use it with a cable as a separate access point.
If you also want to improve your wifi setup, I can recommend unifi. Aruba is also good but they went cloud only and who knows how long they will keep there old non cloud firmware updated.
Das kannst du schon so machen. Was viele vergessen ist, das öffentliches Geld sehr langsam ist. Du rennst dem sehr lange hinterher.