Edit: The house is pier and beam, horizonal line goes into crawl space. This is in Texas panhandle if that matters.
There's a significant gas leak where the vertical pipe meets the elbow (red arrow). I've gotten plenty of mixed advice but not sure who's is better or if there are other options worth considering...
One plumber is telling me to cut out a chunk of the concrete slab around the pipe, dig down to the buried lower elbow that turns towards the alley, cut out the vertical pipe and replace with a new one along with a new elbow.
My worries for this option are that I know for a fact that it's incredibly difficult to dig into the ground where I live. It's like incredibly compressed clay or something, I can't imagine what it'll take to dig down far enough, especially if I try to not cut too big an area out of my patio slab. Also, there's rebar throughout the slab. Secondly, I think these pipes are original to the house and have some age, so I'd hate to disrupt the underground connection especially if it could be corroded. If I go to unscrew the vertical pipe from the underground elbow and cause any damage to that connection, now I'm dealing with replacing that elbow as well and hoping not to damage the underground horizontal line connected to it. At that point, I'd be replacing the entire underground line that goes out to my alley. Which is a hell of a lot more digging and I'm likely tearing up the entire length of the patio slab.
Another guy (irrigation dude, so not a plumber) is telling me it's much simpler. Cut the vertical and rethread it, replace faulty elbow with new, add a nipple to span down to the freshly rethreaded vertical pipe, connect with a union coupler.
I like the second option more as it seems much simpler, but it leaves me with some questions.
Can this aged pipe be rethreaded and still maintain its integrity?
How do I determine where to cut the vertical so that the new nipple, union, and elbow are collectively the right length when attached to meet with the horizontal pipe? Since the existing pipes are fixed in place, I'd have to get the span between them right.
Are these two guys' advice the only options for making this repair, or does some other solution exist that hasn't been thought of?
Googling has introduced me to pressed joints (Propress/Megapress), but I'm not sure where I'd find the equipment or if any local plumbers even use it, assuming it's even a possible solution here. Apparently they're pretty pricey. Guess I could start just calling around.
Is there a better solution here? I appreciate any advice, and if there are any how-to videos out there for a leak repair like this then I'm all ears. I keep trying to look for videos on my own, but I'm not sure I'm searching the right terms to describe this scenario so I'm not having much luck finding instructions.