It’s fine. Location is up to the manufacturer. Size is fine as long as it is not reduced.
Lot of problems on that unit. Where does the TPRV pipe terminate? At this point, size doesn’t matter.
The vent is a bit cheesy…
Biggest concern there is to locate where it discharges. Sometimes they go into the wall, and up out of the ground at the exterior. IF that is the case, then it would have a trap. It cant go down, and back up again. If it just goes in that wall, and out the exterior wall, you’re fine.
However, it could also go every which direction and exit at the other wall on the other side of the garage (I’ve seen it before)
What’s that go to outside?
Note lack of bonding for the hot, cold and gas.
Appears to be leaking quite a bit.
where do u think fault is ? thanks
by bonding you mean bonding wire right?
it terminates outside the garage wall
Just google water heater pressure relief valve leaking. It is not complex and you will have a good understanding.