Didn’t see your post before but just checked and for the T7 it says 900 mA available and 896 required…
That’s pretty close to being more needed than available strictly on the numbers but if the ‘required’ number is anything like what vendors typically say is required for a computer or drive there is almost certainly some buffer in the ‘required’ number over what is actually needed. However…since using a powered hub didn’t help either I’m thinking it’s not a power issue but something else…especially given the all over the map reports that google found for me. All of them were anecdotal but at least from semi-reputable forums and websites.
It could even be something strange since the T7 runs USB 3.2 and the mini is only 3.0…or could be something strange with the USB C to USB A cable that come with the T7. I’ve got a plain C to A adapter plug so I’ll give that a try with a C to C cable on the drive…although I don’t really expect that to change anything.
The power numbers are the same for my T5 and T7 like the ones you mentioned. Both boot Catalina fine on my 2012 Mini. I see the same numbers for a WD easystore which also boots fine. So maybe it is something unique to the newer Mini or it’s a Monterey issue which I can’t run otherwise I would have tried that to see what happens.
You said you’re connected to a Sony tv. Maybe try a regular monitor just to see if that somehow is causing the issue although that doesn’t seem likely.
You know, in your case my gut feeling also says it’s related to macOS and that specific mini rather than the hardware. Perhaps there could be something wonky with the T7’s bridge circuitry, but my money really wouldn’t be on the hardware, especially the cable.
But that said, I’ve become increasingly weary of cable issues. Not long ago I went through a massively odd ordeal trying to get a simple USB-C connection to work using the manufacturer’s included cable, which was neither faulty nor flimsy, and definitely not cheap, and I just couldn’t get things to work. Tried many other quality USB-C cables and nothing worked out. Finally, in an act of despair I tried Apple’s expensive 80-cm TB3 cable and low and behold that did the trick, all oddness went away. NB, this was a USB connection, not TB. And ever since I’ve felt that when you have a kind of odd issue with connecting hardware, especially over USB with all its complicated variants and overly confusing spec terminology, you can’t really try enough cable alternatives and variations. Of course this is assuming you’re curious to truly wrestle this issue to the ground. Otherwise, it’s likely mostly a waste of time. ;)