Ok, so I managed to do everything today
I'll write a follow up here, as it's still related to the treads and sensor installation...
So, the brass extender that I put, in order to be able to have the gauge pressure sensor as well as stock sensor broke. The treads were left in the engine and I was prepared for hours of struggle.....but it was a bit less. Torx or whatever I stuck inside, only spun within. So I took a dremel, slightly notched it and then hammered a wide flathead in it. That finally made it budge
I then took my time and detailed what exactly is preventing me from having enough clearance for installation of the sensor...and I noticed that if I slightly bend a completely irrelevant and unused metal par protruding from the alternator, I can get JUST enough clearance to have it all tightly sitting, without any interference.
I got enough tread engagement, it's tight enough, tested for oil leaks - all good! I also believe this part to be more durable than the brass one, as it does feel like it's steel. Also, since the whole pressure sensor assembly is now shorter, the torque on it is smaller and I believe it will hold on.