R6220 - Toss or Continue troubleshooting?

Let's cut to the chase, I picked this router up at Costco sometime around April or May as my old ASUS RT-N56U started stumbling my connections consistently despite being 2 years of performing like a champ.

To its credit, the R6220 worked great and fast when it was setup out of the box. I was happy with the speeds on wired and wireless as it reached my connection limit 105 Mbps.

But after reading the security related updates on the router, I said sure lets update the firmware (latest one at the time). 

And queue the horrendous performance of the R6220. Wifi connections constantly get dropped, my one PC that is on LAN will at times randomly drop connections to certain programs.

Speed tests on wired drop considerably and Wifi Speeds at 2.4ghz are subpar along with the 5ghz pulling out 50-60 Mbps in the same room as the router.

So I decided to do some reasearch and saw that this router was getting slammed with bad reviews due to connectivity issues and bad firmware. Many of them suggesting to downgrade to V1.0.0.16_1.0.1 and performance was acceptable. 

So the question is, what firmware should we be using for stability and what have others done to increase performance?

Or did I make a grave mistake in not investing more money on a nighthawk series and I should just bin this router?

Before I get a generic response about what I have done with the router...

Upgraded to latest firmware: Yes

Factory Reset: Yes

Channel Monitoring: Yes, I have adjusted the router manually if the channel was congested.

Power cycling all network gear: Yes

Number of connected devices: Actively we have 4-5, 1 PC Wired, Chromecast, 2 phones, 1 laptop.

Tried a different router: Not one on hand.