Major performace problems since 11.3.1 ios update!

I have a laundry list of issues since 11.3.1 update! What is happening!?

It is constantly lagging - typing anything is so frustrating, every character is several seconds behind. It freezes up constantly. Most all apps force close for no reason. Battery drain is excessively fast. (Yes I checked battery health and says it’s functioning at a normal level.) Safari very touchy - some pages NEVER load, especially on data and occasionally WiFi. Safari freezes up constanly, and/or is very very slow! Yes I even went into settings and I cleared all my website history and data, no change. I have tried hard restart several times. Touch screen is even lagging, sometimes not working at all, or have to tap something several times for it finally to “go.” I get a blank, black screen at random moments, no rhyme or reason to it, can be from any page or app. Most frustrating is probably losing in-progress important texts or emails or documents which force close out of nowhere and I LOSE EVERYTHING previously written. This has happened MANY times, and when I go back in, everything is gone. I’ve lost valuable time and information with this problem especially. What else.... oh yes the camera lags and freezes - I can press the shutter and several seconds later the sound effect happens. Orientation also freezes - and no it is not locked.

I have an iPhone 6s Plus which is in otherwise near-perfect condition, so I have no real need for purchasing a new phone. But goodness gracious.....I feel as if I’m being backed into a “it’s been a while since we’ve made money on you - you’re phone is old so we’re gradually killing it to force you into buying a new one” corner by Apple. :/

Is anyone else experiencing these issues, are there any known fixes, are any of these “known” problems, is it related to the 11.3.1 update - it’s the only correlation I can draw.... please help!