Which NEC code sections deal with outdoor junction boxes?
Start with NEC 300.2 and keep reading.
I don’t see an issue the connections are in a box.
junctions underground for UF wire do not even require a box. in that case a listed UF splice kit would be needed (yours appears to be in conduit).
if they pulled the slack from the junction at your box not this one, you may have a case.
Since it is after the meter contact the electrical inspector and ask if a permit was required for the work and did they get one and was it inspected?
The grounding conductor (green wire) is normally required to be an irreversible compression type or welded. I can’t tell but the Polaris connections are acceptable in a box.
the top needs to be accessible not buried. I am not sure if your 4’ comment is the depth of the splice or box top. In conduit this is well below the requirement (safer).
Each jurisdiction has there own requirements that would pass in my state if the green wire is in a crimp connector or butt splice.