Yeah, I am not so sure everyone will be able to run 3733MHz gear 1. That According to Igor's lab
and some other sources, there is a bit of silicon lottery involved there. I know it was an MSI chart, but if you go to that link and look at what they have, it shows the possible memory configurations and while 3600MHz is green as in "everybody should be able to do this", the 3733 and 3866 are in the "your mileage may vary" category. I think the z590 FTW even has some notes there about those being hard to boot.
That said, you have a very similar kit as me. I had to bump mine up to 1.45V to get it stable at 3733MHz 16-16-16-36, but mine is default at 4000MHz 16-19-19-39 1.4V. I don't think you should have to bump yours up, but you could try it. I'd be surprised if that kit couldn't handle it. You could even try 1.425V just to see if a little bump gets you there. They also indicate on that page that bumping up the VCCIO Memory Voltage (Not VCCIO Voltage, I think EVGA calls it VCCIO_Aux) a little may help stabilize memory settings and to make sure that the SA (System Agent) Voltage is between 1.25-1.3V. Again, this was based on another board, but those were the findings they had for the most stable memory settings. You can check the owners thread to see what tuanmassey and I posted for our voltages there. Ours were in "auto" mode, but if yours is doing something strange you could try to adjust it manually. It sounds like Igor's Lab expected to see some board manufacturers' VSA being higher than it should be and that stability could be found by lowering it.
The crappy thing is that Intel only guarantees 3200MHz on these. I don't know what causes peoples' mileage to vary or why you two are having trouble with kits so similar to ones others have gotten working. Hopefully if there isn't a setting you can find to fix, eventually there's a BIOS update with some stability improvements.