Need to replace TX818 with what??

[101mph62]

So I’ve been watching deals and the Denon 3400h is on sale today

My situation is I’m looking at buying a OLED within the next 6 months just depends on finding a deal I like. Going to be replacing my D8000 plasma. I currently have an Onkyo 818 and I’m going to have to replace it cause of no 4K pass through. I have 5.1 setup with M70 series 2 speakers(6.5s) and they are rated at 20-275 RMS and the Onkyo is rated 135 per channel. Sometimes I feel my 818 isn’t enough at louder volumes for the M70s but maybe that’s just me

The Denon is on sale but is that enough power? I really wouldn’t be even looking at AVR but with the 4K gonna need one. Should I pull the trigger on the Denon 3400 at 600 or just wait and see if I can find a better deal. Or should I be looking at higher end AVR all together?