pressure canning starter wort questions

I searched and did not find exact answers to these 3 questions.
#1 do I have to boil the wort BEFORE canning it, or can I just run right from the mash tun to the jars?

#2 with no boiling how do I achieve 1.040 wort with a single batch sparge? I get around 75%+ efficiency but again that is after boiling and cooling etc. how do I figure out how much 2 row to mash to get 1.040 wort preboil? ( if this is super stupid easy remember I have feelings lol)

#3 is pressure canning absolutely necessary? I saw one person saying they hot water bathed em for an hour but everyone else says 15 PSI for 15 minutes.

I collected the left over wort that drained from my mash tun. It was a pretty low OG.
Here's what I did:
1. boil jars ,rings ,and lids
2. bring wort to a boil
3. fill hot jars with hot wort
4. screw lids on
5. let sit on counter 24hr Do Not Touch them.
6. keep them in the fridge

I keep them in the fridge because I did not pressure can them. If you want to make them shelf stable them I would run them in a pressure caner.

1. We were having a discussion about this recently so you can read https://www.homebrewtalk.com/f36/pressure-canning-wort-question-356032/ to get some ideas.

2. I just put 0 minutes boil time into my brewing software to help me calculate it

3. Pressure canning is the safest bet and allows you store them without refrigeration.