I am sorry to learn that you are experiencing touch screen issues with your fairly recent 2018 iPad Pro model.
I believe that your 2018 iPad Pro may have contracted an serious, hardware related, intermittent, unresponsive touch screen issue/problem/bug/flaw.
This is a well known issue here in these iPad support communities.
This unresolved hardware intermittent, unresponsive touch screen problem affects a continuing, growing minority of iPad Pro users/models across all 4 years of iPad Pro models, as well as the new 2019 10.5 inch screen iPad Air 3, which is based from the 2017, 10.5 inch screen iPad Pro models.
Take a look at these long standing, longer posts on the subject of this intermittent, unresponsive touch screen
issue, below.
There is STILL no “official” confirmed iOS updates, solutions/fixes, from Apple, after18 months, now!
No type of fix/solution forthcoming from Apple, to date!
None.
I do not believe Apple will ever come up a fix/solution for this intermittent, unresponsive touch screen issue.
Because this issue is either STILL only affecting a growing, but still very small minority of iPad Pro/iPad Air 3 users OR iPad Pro/iPad Air 3 users are simply NOT reporting this issue enough here in these official Apple iPad support communities OR simply NOT posting enough feedback to Apple about this intermittent, unresponsive iPad Pro touch screen issue to alert the proper responsible and cognizant Apple employees and teams and get them working on this iPad Pro touch screen problem.
iPad Pro touch screen intermittent unresp... - Apple Community
https://discussions.apple.com/thread/250085450
iPad Pro screen unresponsive - Apple Community
https://discussions.apple.com/thread/8658399
iPad Pro 12.9” not responding to touch in... - Apple Community
https://discussions.apple.com/thread/8396370
The best you can do is to continue to alert Apple to this growing issue and hammer the Apple iPad feedback pages mutiple times on this issue.
I implore you to submit feedback to Apple on this large screen iPad touch screen issue.
The only way to get Apple to, DIRECTLY, listen to you is to use their feedback portion of their website.
iPad Feedback
http://www.apple.com/feedback/ipad.html
Cognizant Apple employees read ALL feedback generated from all of the various feedback pages and transfers the data to the proper and responsible Apple teams and personnel , but NO Apple employees will ever respond with any type of direct, individual replies from the feedback you post.
You can post as much multiple feedback about this issue any time.
The more users that post product feedback about any product issue, the faster Apple is made aware and starts working on a fix/solution for a future software update.
As I stated, this intermittent, unresponsive and unresolved iPad Pro touch screen issue has plagued a small, but growing minority of iPad Pro users across all 4 years of iPad Pro models for over 18 months, now!
If you are able to do this, I STRONGLY suggest contacting/reaching out to Apple Product support and services on this larger screen iPad intermittent, unresponsive touch screen issue and if you have to, escalate this issue to higher levels of Apple customer support personnel to get their attentions on this issue.
Tap on the first link below and scroll down some to get to the Apple Product Support section and phone numbers for your location/region.
https://www.apple.com/contact/
OR
https://support.apple.com/en-us/HT201232
This is a serious, unresolved hardware/software problem that has been plaguing a growing minority of iPad Pro users, across all model years, for the past 18 months, or so.
For iPad Pro users, this intermittent, unresponsive touch screen issue started waaaay back with either a late iOS 11 update OR with the introduction of iOS 12.
There is NO resolution for this from Apple, to date.
Sorry that your 2018 iPad Pro has contracted this most vexing intermittent, unresponsive touch screen issue.
You are now part of small, but still very much a growing minority of larger screen iPad users that have been affected by this intermittent, unresponsive larger iPad touch screen problem/bug/flaw.
Sorry & Best of Luck to You!