Hi Fakuu,
It really sounds like you've done as much as possible with fixing the phone via software. At this point it really sounds like you have an issue with the digitizer; the part of the screen that handles the touch input. It is not at all uncommon for them to fail and when that happens the only solution is to replace the screen.
iFixit has just the thing for you; a step by step guide to doing the repair yourself.
iPhone 11 Screen Replacement - iFixit Repair Guide
I've done a fair amount of screen replacements, so let me drop a couple of thoughts on the process. First of all, as Elmer Fudd would say, be vewy vewy careful replacing the earpiece speaker assembly. If you damage it the only way to fix it is to pay Apple for a full screen replacement.
I'd suggest picking up a couple of the precut adhesive sheets to glue the screen back on when you're done; the thing is, they're easy to mess up and they're not even a little bit forgiving if you don't get them on right the first time. If that happens there's no fixing it; you just end up with a tangled ball of glue then you have to wait however long it takes to reorder a new sheet. Trust me, I speak from experience.
Other than that, follow the instructions and make sure you do a good job cleaning the old adhesive off the chassis before installing the adhesive sheet and you'll be fine.
There are a couple of gotchas that Apple has built in on screen replacements. First of all, the True Tone function will no longer work unless you read out a piece of data from the old screen and program it into the new screen with a device programmer like the V1SE or iCopy programmers. The data is usually copied from the old screen but can be retrieved from the phone itself if need be.
Secondly, Apple has started pairing the screen with the logic board. Since they're the only ones who can do that pairing, you're going to end up with a pop-up warning when you log in that the screen may not be genuine - this will happen whether you use a genuine screen or not. That warning will go away after a couple of weeks but the same sort of warning will remain in the settings under the display permanently. Again, the only cure is to pay Apple to replace the screen, otherwise you just have to live with it. Unfortunately you can't even use the self service program because the oldest phone they support on that is the iPhone 12.
When you go to order a screen, you can of course support iFixit's repair efforts by purchasing it from them; I'd personally recommend the Fix Kit version since for only $5 USD it comes with the screen adhesive and all the tools needed to do the job. Otherwise you can find replacements readily available on sites like Amazon, eBay and AliExpress.
There you go; you asked for advice and I wrote you a book, so sorry about that but hopefully you have enough information to make an informed decision.
124 
44 
91 
