You might want to draw out some pics of what you are talking about. A nice sketch uploaded will do.

This is a simple drawing.

Hire a very good plumber and listen to what they say.

Yeah, that was helpful. If I wanted a plumber I would get one. I like doing things myslef and learning...but thanks for your words of wisdom!

Some things are best left to the pros and plumbing if a simple job no problem DIY. But if you do not know what you do not know the price you pay is not worth the learning when the house floods and insurance won't pay.

So, I got a line camera and scoped it. The drain goes about 35" and then has a 45 degree corner and then about about 12" or so is a multi port, two different pipes converging on this one. I think the its the vent pipe and something else, maybe sink or the main stack.. But right at the first 45 degree turn is right where I need to turn it to go to my new drain position. I think the best plan is to drill/chip a large hole in concrete right there and see how to change the direction to make it go toward the new drain location.

Why not consider a linear drain? That's what I did (that is, my plumber did this) in my tub to shower conversion. I used this "magical" shower drain body by Infinity Drain -- it is flat on one edge and allows placing the drain close to the wall. This is on a 2nd floor bathroom -- I did not have a problem with concrete slab but there were supporting beams in the ceiling below that prevented moving the drain anywhere else.

I’ve seen this "tub-to-shower" struggle in countless basement renos across the GTA. I totally respect the DIY drive to learn, but concrete slab work is definitely a "measure ten times, cut once" situation because the physics of drainage don't care about our floor plans!

The most important thing to understand here is that a shower is not a tub. In Ontario (and most jurisdictions), a shower requires a 2-inch drain line, whereas your old tub likely used a 1.5-inch line. If you just adapt a new center drain into that old 1.5" line, the shower floor will likely fill up with water faster than it can drain.

Since you've already got the camera out, here is how you handle that 45-degree "2 o'clock" situation professionally:

1. Forget the "Tap Off After the Trap" Videos

Those videos are often showing best-case scenarios that lead to major clogs. You cannot run 3 feet of pipe after a P-trap before hitting a vent. You will create an "S-trap" effect which will siphoning the water out of the trap, letting sewer gases into your bathroom. The P-trap must be directly under the new center drain.

2. The Chipping Strategy

Since your camera showed that 45-degree turn roughly where you need to be, that is your "Golden Ticket."

The Goal: You need to chip the concrete back to that 45-degree fitting.

The Connection: Cut the line before that 45-degree turn. This gives you a fresh start. You can then run a new 2-inch PVC line straight to your new center location, install a new 2-inch P-trap, and you’re golden.

3. The "2-Inch" Rule

Check that pipe you scoped. If it's 1.5-inch copper or ABS, you really should chip back until you find the 2-inch (or 3-inch) "trunk" line. A modern high-flow shower head will easily overwhelm a 1.5-inch drain, especially if there's any hair buildup.

4. Slope is Everything

In Ontario, we look for a 1/4-inch of fall per foot. If you are moving the drain 3 feet away from the original stack, your new drain needs to sit about 3/4-inch higher than the point where it connects to the main line. Make sure you have the depth in your slab to allow for that slope plus the height of the P-trap.

Pro Tip: Since you're doing this yourself, once you have the new pipes dry-fitted, do a "bucket test." Pour a 5-gallon bucket of water directly into the pipe. If it gulps it down instantly without backing up, you've done it right. If it burps or drains slowly, you've got a venting or slope issue to fix before the concrete goes back in!

Maybe he already did it since he does not come back to check any real help.