Used AV Reciever for 300€ (2 Viewers)

[schnaeja]

Hello. I am building a 5.1.2 Atmos setup and still need a fitting AVR. Since I have a pretty tight budget I am looking for a used one and I found 3 AVRs.
My speakers:
2 Pioneer CS-970s as Fronts
1 Canton AV500 as Center
4 Canton Plus X as Surround and Height speakers
Suwoofer is Diy

So the following recievers I found wich I can fit into my budget:

Onkyo TX NR 686
Denon AVR-2400H
Denon AVR 4200W

Wich of these is the best and do you have other AVRs that fit the budget?
Thanks!