Install Delta shower valve in space with copper vent pipe

[goals123]

Ripped out shower walls and alcove tub in a renovation. Planning to install Delta multichoice universal shower valve, install asks for 2x4 blocking behind. Have installed in a previous renovation but I’m not an expert. After opening though found there is a copper vent pipe right next to existing valve, they have a small piece of wood diagonal crossing in front of the pipe then behind valve for support.
Question is how should I install the delta valve? The shower head further up has a thin wood with a notch for backing, could try that but not as much space near valve. Also the copper water feed lines are pretty close to the back, they 90deg bend out before going in to valve. Was planning to reuse copper lines, solder to delta valve, but perhaps I have to bite the bullet and learn PEX?

 

[John Gayewski]

Can you change the drain and vent configuration? It's not legal or advised the way it sits.

 

[Sponsor]

 

[goals123]

This is 2nd floor, that vent pipe goes straight up into attic then out through roof. Moving vent pipe would mean new hole through roof (I think? Unless it can have a bend in the attic? Do vent pipes have to be straight?).
I was thinking this config was…not standard. No idea why they would do it this way. Is there a danger as is, or why is it not advisable?

 

[John Gayewski]

Your vent is horizontal under the floor. I would be curious to see if the straight run of that wye in the floor is plugged.

 

[Jeff H Young]

I see no issue with installing a shower valve as you can see this has male adapters which stick out more no problem with the vent but put all the bends you want.
The issue I see is that entire mess of white pipe that all needs to go and dont use slip joints unless you have acesss.
Let us know if you need tips on how to do the waste lines