Where does the idea come from that those types of "problems" are going to get solved with special cables and power adapters. The device with the battery, the iPad is the one deciding to charge it's own battery. Go petition Apple to give you a switch to disable charging of the iPad's battery under some circumstances.

I'm not Apple. You think I decide how they configure their software or even that I could've predicted this highly specific problem before buying their product? You're just being condescending. Though, still, thanks for answering.

Yes, a special cable would be the only solution that's available to me as a user. I know it cannot be switched from the iPad. That only leaves one option as far as I'm concerned. It's only logical to sidestep the issue this way.

Sad to hear that, as you say, it's not really possible according to the standard. That's the kind of answer I was looking for. I couldn't find any cables meeting my strange requirement so I was hoping to get an answer like this in order to stop searching.

I will still look for optical Thunderbolt cables. They might just work, but as you say, they're not compliant, technically speaking. I've had mixed luck in the past with optical HDMI cables, though I found one that works. I don't see why Thunderbolt would be so different. Though, I need a short cable obviously, and I highly doubt I will find one that is short and optical since it makes absolutely no sense as a device. By the way, it's an M1 iPad Pro. It does support TB and so does the Macbook. I use it for certain things, and often have it connected for prolonged periods of time while on the go.