Had this with the RAXE450 and worked with ProSupport for hours on end, for days, with no luck

I have the 1.2Ghz plan with Xfinity. Typically I've been hitting above 1.4 Gbps, but sometimes it spikes above 1.5 Gbps (doesn't last long but it hits), 

When my neighbor let me test it, I was in his apartment, in the same room as his router. If I hit those speeds from my apartment with his router down the hall, I would've tossed the RAXE500 under a freight truck lol.

You're right about the speed tests with Ookla. I do confirm with the Xfinity speed test to make sure they're not that far off.

The ProSupport L2 support folks can't figure it out either. I've also bee seeing more and more people posting similar performance issues with the RAXE450/RAXE500 units, recently.

Only thing I can think of is that Netgear may have started using alternative suppliers for their components for their hardware since the supply chains choked up. My neighbor works on automotive electrical panels and his company has had to pony up for inferior components since semiconductor supply chains have been choked up. So paying more for lower quality parts. Even AMD and other semis are screwed.

I can't think of anything else.. I have another follow-up call with another L2 support technician today. If they cant sort it out by now, I have to return this unit by the weekend and go with another manufacturer at this point.