Thank you for telling me Ashley!
With the Apple Developer Account thing, a free developer account gets you 3 apps to sideload, which expire every 7 days, (replenishing them, not gone forever) until you use a computer to renew them. With a paid account, you get unlimited sideloads, and they expire after a year.
I want to sideload to older devices, such as an iPad Air 2 (iPad-5,3) on iPadOS 15.8, or an iPod Touch 5th Generation (iPod-5,9) iOS 9.
If Construct 2 does not support exporting to iPadOS 15 if it's maybe too new, or if it doesn't support to iOS 9 because it might be too old, I can go through the exported IPA file (if it does export in that structure) and recompile it.
Again, thanks Ashley!