Tiles or panels is completely up to you, but after a full gut I would use tile 100%. In LA a condo would in my opinion call for tile were it to be sold so there is that. I would certainly think you need to pull permits and I would want to in part just to 100% sure the shower is built properly, and even then, trust but verify.....................

You need a better contractor than whomever built that. YES, you need permits and inspections. That lack is probably why what you have is leaking. https://www.ceramictilefoundation.org/homeowners-guide-to-hiring-qualified-tile-installer

You’ve got two separate issues here, and most people mix them up.

First, the leak.
That’s not a tile vs panel problem. That’s a waterproofing failure.

From your photo, the issue is very likely coming from the shower system behind the tile. Either the pan, the membrane, or how the glass was tied into the wall. Changing to panels without fixing the base system just hides the problem for a bit, it doesn’t solve it.

If water is already getting to the unit below, this isn’t a surface repair. The shower needs to be opened up and redone properly from the waterproofing layer out.

Tile vs panels is more about finish and maintenance.

Tile gives you more flexibility and usually looks better long term, especially in a condo where you want it to feel like part of the home. Panels are faster and have fewer grout lines, but they can feel more like a system install unless done really clean.

Either one works if the waterproofing is done right. Neither works if it’s not.

Second, permits.

In Los Angeles, once you’re opening up the shower and touching plumbing or rebuilding the pan, you’re almost always in permit territory. (Aggregate Construction Group)

If it were just swapping finishes in place, different story. But a leaking shower means you’re dealing with the system underneath, and that usually triggers inspection.

Also, since you’re in a condo, HOA is just as important as the city. A lot of buildings require approval before you even start, especially for anything involving plumbing or potential water damage.

One thing most people don’t realize
In condos, bad shower work doesn’t just affect you. It becomes a liability issue with the unit below, and that’s where things get expensive fast.

If this were my project, I wouldn’t even think about panels vs tile yet. I’d focus on rebuilding the shower correctly so you don’t deal with this again in a year.

If you want, I can walk you through what a proper shower rebuild should include so you know what to look for when talking to contractors.

I am in the middle of a bathroom remodel in LA County. To obtain a permit, you will need a letter of approval from your HOA.

The waterproofing process for showers that is typically used in Southern CA is considered "old school" by other parts of the country -- and it works well here:

1) hot mop (tar) on the shower pan and about 12 inches up on the shower walls, followed by a flood test inspection by the City

2) insulation on the walls, followed by insulation inspection by the City (not waterproofing, but needs to be done before the next step)

3) paper&lath on the shower walls, followed by City inspection

4) scratch coat on shower walls -- wait for it to dry

5) brown coat on shower walls (also called "cement") -- wait for it to dry before installing tiles

There is one more inspection -- final inspection before the bathroom is considered to be operational.