Figured I'd keep this going as I have the same issue and am also near to returning my system (2x eero 6 Pro)

Gigabit coming into house.  Eero wired to modem shows ~950Mbit down consistently in the eero app.  Any devices that connect to that eero get 300-600Mbit (using speedtest) depending on connection quality.  If I connect, however, to any of the meshed units (I have 2 of them), the best I can get is 150MBit and it frequently dips below 100Mbit.  This results in terrible video calls.

I've tried relocating the 2 meshed units to different locations (some close, some far), using them only one at a time, etc....but consistently all I can get is <150Mbit on those satellites.  House is about 3k square feet but also need access in detached garage.  If I only have the main eero 6 Pro connected with none of the satellites, I don't get enough coverage.  I need the mesh to work.

Steering is enabled (by default, now, in the app).  I've tried other things in this thread.  I'm convinced that there's something poor with the way that the eero 6 Pro implemented the fronthaul radios when in mesh mode.  

I bought these because I was previously using a Google Home mesh but also dropping calls sometimes.  We upgraded both the internet (from 300M -> 1G) and the eeros.  Not simultaneously....eero's first and when that didn't fix the problem we upgraded the internet and replaced the modem.  As long as I don't use eero as mesh, it works great.  But unfortunately, mesh has to work.  Back to Google Home?

I also have 6 devices on a large footprint property. I've separated 4 as far as I could and moved two to the far corners of outbuildings and the performance has shot up. Too many device tread on each other  it seems.

Can anyone say class action lawsuit. This thread is HUGE and I don't a solid answer. I have to reset everything two or three times before I get my expected speed back. It only lasts about 5 says or so and the BS starts again. 

Have Frontier GB and received 2 Eero 6 Pros with the service.  Getting really crappy wifi speeds, sometimes 160-170 mb in the same room with the Eero.  At this moment 400+ up/down.  

Ruled out Frontier problem - close to 1 GB up and down when connected to router by ethernet.  Ethernet connect to Eero also 900+ up/down. 

Contacted Frontier.  After "investigating", tech told me I should upgrade my service cuz I have "so many" devices connected.  Geez. They teach 'em well, right?  Every problem solved by selling more!

By the way, out of about 40 devices that could be connected at any time, 90% are smart switches & plugs & Google home devices, a couple of printers, a solar inverter, an Elon-mobile, etc.  I don't know for sure, but doesn't seem like those things would be sucking up a lot of bandwidth at any given moment.

Then I found this thread.  Problem solved, sort of.  Per reporting in this thread, shouldn't expect wifi speeds to be better than around 50% of the connected speed.  The even slower speeds on the 2nd Eero have also been explained.

Gonna dust off the DLink AX5400 I had purchased a few months before receiving the Eeros.  If memory serves, the DLink was broadcasting speeds similar to the connected.  We'll see.

Thanks to everyone who shared their research in this thread!

@garyg Thanks for the info.  Will check out the analyzer, but you have a different model of Eero than most in this thread.  The plan Eero 6 Pro (not the 6E model) doesn't have the ability to leverage the 6GHz band as it only supports 2.4GHz and 5GHz.  I suspect that this is not only a channel congestion issue but also a chipset or firmware issue with our particular model that does not re-steer to clearer channels. 

Im trying to get wifi 500 ft distance from the modem. I purchased the pro6e mesh. I'm going to hardline with outdoor cat 6 from 1st rputer to 2nd and third. Does this sound possible? I notoced when i set up the first router it came in lower then the company provided router but the farthest rputer was faster. Wierd.