Most likely leaking because no one sleeved the line passing through the concrete. Without seeing the layout it's hard to offer advice. I do like the flex suggestion. Enter the home with a pipe nipple long enough to connect to the meter. Put a metal header designed for flexible lines on the end, or build a header using T's in the home. I like the manufactured headers since they eliminate potential leak sources. Pull the line to where it needs to go. The flex line is stainless steel with a PVC outer coating. It's easy to work with and if there's a leak, it's at the header or the point of use. For leak testing I went with piece below. I quit using black pipe years ago. I have all the tools to run black pipe but it's too much like work.
OH YEAH! No matter what you pass through, be it a concrete wall or wood, put a sleeve over the line. I typically use a plumbing tailpiece large enough to go over the line that enters the home.
Tools needed: Tubing cutter for flex line, two adjustable wrenches. Maybe a hammer if you have to install pipe hangers.
Leak test:
https://www.menards.com/main/plumbing/pipe-fittings/flexible-gas-pipe-fittings-accessories/pro-flex-trade-bell-test-gauge/pftg-b1230c/p-1699697311238222-c-9529.htm?exp=false
Gas Line:
https://www.menards.com/main/plumbing/pipe-fittings/flexible-gas-pipe-fittings-accessories/pro-flex-trade-csst-flexible-gas-tubing/pfct-3425/p-1444445271632-c-9529.htm?exp=false
Header:
https://www.menards.com/main/plumbing/pipe-fittings/flexible-gas-pipe-fittings-accessories/pro-flex-trade-4-port-cast-manifold/pfmn-bbb/p-1444445270978-c-9529.htm?exp=false