iPad can't install iOS updates

Thanks a ton for the insightful links but none of them describe a situation like mine. As i said the progress bar appears and seems to be working fine but the device just restarts after about 10 seconds, with the bar obviously only partially fullfilled. I surely could try restoring the iPad and i'm pretty sure that would solve everything but i don't know if that involves losing data or apps that i wouldn't want to have to reinstall. I'll do that if it's necessary by the way but i'd like to know if there was a more specific solution to such a problem.

Also, i tried performing the update from iTunes but nothing seems to happen when i click the "Update" button. It just stays clicked for about a second without doing anything. Don't know what to think.

As i said not even the iTunes method seems to be working for me. I don't know if some additional procedures are needed but i tried connecting the iPad to my computer, authorized it and went to the device page of the program. There's a pretty evident "Update" button but that doesn't react to my solcitations. I click it, it stays clicked for less than a second and returns normal. Have i to put the iPad in recovery mode even to perform a regular update?

I was having some problems with Windows Update so the latest version of my Microsoft Store version of iTunes was not showing up. I seemingly solved everything and after updating the program things seem to be working better. Clicking the "Update" button actually started the installation procedure and as of right now the software is being extracted. I'll inform you later on how it goes.

It took some time but i got news. I initially encountered a problem during the automatic backup iTunes performs before starting the effective installation of the O.S where the device kept virtually disconnecting from the computer, forgetting about it and asking to give it the authorization to access it again and obviously abruplty interrupting the whole process. Fortunately switching USB port was enough to solve everything and let iTunes put the iPad in recovery and start uploading iPadOS. I don't know how but it worked. It took a little longer than what i remeber was necessary for an incremental upgrade like this one but after at least ten minutes the tablet successfully rebooted welcoming me to iPadOS 14.4. I hope i won't have to go throught all of this for every next release but thanks a ton anyway. I already thought of doing something like this but didn't really believe it would've worked. Thanks again and bye.