Iced Soul

Okay that would explain that ping then, I still don't believe you need it for SQM but yes it does have the same implementation as the R3 currently although in Early Access though you can try pre DumaOS 4 but you won't get many more updates for that router.

You're using it with 1 device only? Exitlag may improve the routing to the game servers if your routing is less than optimal. That's a fairly high ping, where abouts are you located?

SQM isn't really new per se and is already what we offer with our QoS solution which will only get better with the next update we're working on. 
It really depends on how you're going to integrate your gaming router into your setup. If for example your setup will be:
Main Router (All Devices Connected) > Gaming Router (Just Gaming Device Connected)
then QoS/SQM is irrelevant because the router won't be able to control the entire network. It would only be able to control the gaming device which from the gaming router perspective isn't competiting with any other device. However, it's actually competing with every other device connected upstream to the main router. If you really wanted to do it this way then the main benefit you would get would be from using the Geo-Filter on the R3, something no other gaming router has.
If for example your setup will be:
Main Router > Gaming Router (All Devices Connected Including Gaming Device)
or some variant of that then QoS/SQM is a lot more relevant as it can control most if not all (it really should control everything for max effect) of the devices on the network. In which case I'd still suggest the R3 for our current QoS implementation but then even more so for the next iteration of QoS that we have planned.

This blog may help: https://netduma.com/blog/how-to-fix-bufferbloat so our current implementation, Congestion Control & SmartBOOST is literally a form of SQM. The ACC referenced there is what I mentioned we're also working on that goes beyond this. 
As before, the fact you have a whole connection I assume purely dedicated to gaming even further reduces your need for QoS/SQM as that's only working on your side of the router to reduce bufferbloat/lag etc but with literally an entire connection just for gaming it really isn't needed. So if that is correct then the R3 would be the one to get with the idea that ACC will be more useful for you in the future.