Keyboard/Typing is lagging and glitching before and after 18.3.1

iPhone 12 Pro Max - recently updated to 18.3.1; Keyboard/Typing (on any app) is nonstop lagging and glitching; the glitch is placing the cursor elsewhere randomly, mid-text, making it lag even worse. Typing/texting has been unbearable the last few days. I am a serial texter, and a fast one, but I am about to snap and had to try and refrain for the day. This started just prior to AND since updating to 18.3.1.

I figured the update was overdue and causing the issue, but it's still happening since the latest update.

I've turned it off and on, cleared caches, reset and cleared everything suggested online (and more).

WTH is going on?!?? Any advice?

...PLEASE do not tell me to upgrade - a $1,750 mobile phone should last a lifetime, or AT LEAST a decade!!!

TIA <3