The good thing about the Denon AVR is that it automatically assumes the appropriate impedance of the speaker during setup.

I already had 2pcs B&O RL6000 and 2pcs B&O CX100 and 1 Klipsch R-52C and ELAC subwoofer.

Hello Bhouw, if I understand correctly, the Teufel Ulitma 20 Surround consists of 4 shelf speakers, a centre speaker and a sub-woofer. All have an impedance of 4-8 ohms.
With these technical specifications and a power of 100Watt/speaker, the Denon AVR-S650H fits perfectly.
I can recommend the Denon myself and mine works perfectly.