I would consider a UPS that's also an AVR. I've got two of them, the first one I bought way back in 2009, (due to our local power being very on/off/brownouts back then, so why I needed an AVR version) and it's still running perfectly. Though I don't also have an Ecoflow, I DO run these UPS's on a diesel generator during power outages, and I've NEVER had any issues with my electronics acting up since they were installed. The older models I have are discontinued, but here's the newest one. You can also replace the batteries when they need replacement in like 5 years or so:
You might not need a bigger model like mine are, but for sure consider an AVR version. It's better for electronics.