I think Black Gears Devimon might be stronger than Etemon, I just don't really know because plot often determines the result of battles like these rather than strict adherence to power levels and type matchups. On one hand MetalGreymon gets treated like a joke by Vamdemon while he definitely feared Angemon to an extent, and MetalGreymon was at least as strong as Dark Network Etemon, but you could just say Angemon gained experience from killing Devimon and then participating in that fight against Vamdemon for the first time, and that experience wasn't reset by his death and rebirth. It's pretty hard to say honestly, and even the exp points from fighting Devimon thing seems like a hard sell when Patamon couldn't even digivolve at will until reunlocking his Angemon form against Vamdemon that night when he and WereGarurumon fought him together.
Again, while I don't think Adventure's power chains are a huge mess like GT or DBS, they're still wildly dependent on the situation and the plot's needs. Which I guess a lot of shonen are guilty of like how the Thunder Brothers did more damage to Tessaiga's sheath shield than a fucking Kongosoha did much later on (same attack that'd rip through Naraku's strongest barriers like a knife through butter), as well as Zabuza being implied relevant to Shinobi War arc Kakashi despite how ridiculous that is when Kakashi fought FAR stronger opponents than Zabuza and did decently even before the war. But two wrongs don't make a right. It just muddles everything and makes it hard to judge. I want to keep things simple and have Etemon or at least Dark Network Etemon above giant Devimon, but Angemon's performance against Vamdemon and Piemon makes that simple power chain a headache to rationalize. And one thing I hate most of all is being dishonest for the sake of making an argument in my favor. I'd rather be uncertain than a liar.
