Potential PdaNet+ trial workaround. (No sketchy APKs needed, no file modifications)
(Instructions based on a Galaxy S20)
Disable cellular data on your phone. (from the drop-down menu it is the side-by-side up and down arrows ((you'll likely have to customize the buttons on the menu to add it))) (unsure if airplane mode works - if you try it and it does work, please say so, unsure if toggling cellular data is available on most phone brands)
Enable tethering in PdaNet+ on your mobile phone.
Connect on your PC/laptop/whatever (it will connect and say that there is no internet detected from your phone through the PdaNet notification toast)
Re-enable cellular data on your phone.
Enjoy not getting disconnected.
(Please bear in mind that this just may be a fluke that works in my favor. If it works for you, please say so, if not, I am sorry - I cannot help you, this is from the results of a trial and error process I went through after the FoxFi Key app was removed from Google Play Store prior to me getting the S20.)