Reviews and tests for Ecoflow units show a clean sine wave with very low THD.
More info and troubleshooting needs to be done. I looked through the manual briefly. A bit sparse for info.
The display shows how many watts you're pulling. For what you have running on it, seems you should be okay.
So. How many watts are you pulling? Ever get an overload indicator, no matter how briefly? Fully charged?
Plugged into a power source or running stand-alone for a shtf test?
A bit fuzzy. You mentioned plugging your UPS into the station. That's a bit strange. A UPS (what brand/model?) may have a switchover time. The Ecoflow will also. So in reality the receiver detected a power loss. Perhaps not long enough to make it look like is shut down.
Like the internal power supply to it "dipped" in the transition period the UPS switched.
Or the UPS batteries could be degraded and the inverter voltage compensation time increased.
What is the power draw with UPS on it only and batteries supposedly fully charged? Good UPS batteries should show low mains power draw.
SMPS convert AC to DC immediately then "make" regulated DC output. So "dirty" AC input voltages, not so pure sine waves. Should not matter. The sat receiver and Sony both use SMPS.
My test was for a shtf event. I have the Dish receiver, Cox Modem, SimpliSafe brain, Roku Ultra, Samsung soundbar and a weather station plugged into the UPS.. It is easier to plug in the UPS cord instead of individual items.
I don't remember what brand or model UPS I have, but I suspect it is a Cyberpower. I can't get to it to see. I have had it about two years, I believe it is this
ST900U.
On the next test I will plug in the individual items which will be the Dish H3 receiver, Roku Ultra and soundbar. The H3 will have to reboot being I will be completely unplugging it. I may run the Sony TV that is plugged into another UPS in it also.