https://hipages.com.au/article/how_much_does_it_cost_to_move_plumbing_fixtures is a good summary of this.

When I was talking to a plumber about my ensuite reno he said as a rule of thumb it was about $1000 for every metre he had to move the plumbing on a slab on ground ( not suspended). But he charged it at an hourly rate and advised it could be half that or double.

We decided to leave the plumbing where it was, but we didn't have a compelling reason to move it.

The main bathroom was a suspended slab and changing the plumbing around didn't really add to the cost of the job at all.

Without knowing how the move relates to the current sewer and if you’re needing gas relocated, I’d allow two days work at $1k per day plus about $700 in materials. You’ll need more labour if the site isn’t clear (everything removed and stripped out) and easy access inside and out. You’ll also need more of the new location can’t easily tap into existing sewer. This is based on rates I’m seeing at work for minor refits (health/education premises). But the only real way to know is to find someone who will do it and then ask them.