Unresponsive iPhone 11 Touchscreen

I've had my 64GB iPhone 11 for 3 years and have never had any issues with it. The night before last (so about 48 hrs ago), the touchscreen became unresponsive. Not entirely, I can unlock it and open apps, but enough to make it functionally useless / unusable (can't accurately type, scroll, etc). The screen is in very good condition and I didn't drop it or anything, it just randomly became unusable.

The only causes I could think of were that the charge was low at the time (4%) and I have recently changed contracts (about 3 days earlier, switching providers), but after looking on Apple Support, it seems as though this is a problem thousands of people have had since November, with Apple having offered little in the way of explanation / solution.

I've tried all of the suggested solutions, including a hard reset (vol up, down, hold side button), which appears to be the only one that has worked for some people, but sadly not for me. Others who weren't able to fix it that way appear to have been unable to find a fix at all and have ended up buying a new device, whether Apple or Android.

Unusually, this didn't happen after updating to iOS17, like with others, but with iOS16, though I have since updated to iOS17 as an attempted fix (didn't work). Also, in the last couple of hours, I've started having difficulties with the port (intermittent charging / won't connect to Mac) - I'm unsure if this is related or just a port issue but thought I'd mention it just in case.

I had my last iPhone about 7 years, and I wasn't planning on replacing this one anytime soon, having had no problems until two days ago - but now fearing I may have no alternative, and obviously I can't go too long without a functioning phone.

Any help or advice is much appreciated - thanks!