As the OP of this thread, just coming back to report a happy update!

In regards to the steaming issue, turns out, it was 100% the tip.

I got around to trying out the stock tip and with no problems, got perfect microfoam again! Phew!

I got a carton of milk a couple days ago.
Yesterday's steaming session with the new 4 hole tip from ep, was once again horrific.

The volume of milk barely rose. The temperature rose way too fast. And all that occurred was boiled milk basically. Also noticed that there was not much steam pressure, but now it's clear why.

Today the 2 hole stock tip got installed.
Using milk from the same carton, the steaming was flawless.
It took the nice proper comfortable time to steam, and a nice sight to watch the volume of milk rise its way on up. No large bubbles whatsoever, only fine microfoam.

Also, there is a lot more steam pressure again.
I gather what's occurring is that the 2 holes are causing more resistance in a good way vs the 4 hole.
The higher resistance creates more actual steam and more control so the milk just doesn't rapidly boil away.

Very happy now. May still be in the market for a new tip (2 hole of course), as the stock tip where it's knurled, almost looks like chrome plated plastic but it's not of course. So it's more for a looks reason.

So all is well on that end.
Although the brew pressure needle is still acting weird. Actually, today it really went haywire! It was violently vibrating not from its typical 9-9.5 bar 60+ times a second, but from 2-9.5 bar, so fast you just couldn't see it anymore.
Surprisingly the shot still did pull decently though.

Oh, btw, just to correct some of the info in one of my posts above, the gauges typically read 9.5 for brew pressure, and 1.0 for boiler pressure. I finally really made note of what they actually said.

Re the crazy needle: As Mark mentioned, could still take time for the seal to set in the OPV. I sure hope so. I hope it's not something drastic like a leak at the boiler if that would even cause that symptom.

Either way, just wanted to report the nice update in case anyone in the future is ever curious what happened to their steaming after they upgraded a steam tip.