Pic of the floor

I would remove the artificial grass and install outdoor porcelain tiles which are most likely not thicker than the artificial grass you have. Also, I've owned a few condos where artificial grass installation was not permitted on the concrete balconies, it's apparently not good for the concrete.

Pick the most beautiful flooring you can find. Forget about the thickness. Once you've found and secured your flooring, you'll know how much topping material you'll need to add to your railing. Thick of the railing on a Superyacht.

You could consider hiring a specialist in concrete floor coverings--they do wonderful colors and patterns in high-end garages. I think that it is epoxy.

Remove the grass then see wht the height is and honestly 41.5 will probably pass code . Have you looked at the teak tiles they just lay on top with no adhesive and look nice but what is the furniture that is going our here and your style , Epoxy certainly could work too .

You could apply an acid wash to the concrete. You can achieve some beautiful colors and patterns with it.

The UV will kill anything you put out there that isn’t porcelain. Having a floor drain is a killer for porcelain unless envelope cut like a shower using large format. A nice wood look tile like Saddle Brook XT would bring in the natural material tones. https://www.daltile.com/products/Wood-Look/Saddle-Brook-XT

Daltile has a whole series of exterior rated porcelain. No natural stone though, in freezing areas. https://www.daltile.com/xteriors/outdoor-floors

Is 42 the height with or without the grass?

42” was without thw grass. I took it at 3 places and one of them was more like 41.5”

How would Daltile compare to something like porcelanosa outdoor tiles? They also have outdoor tiles with similar look.

Then you need to be careful as per code the railing height needs to be 42" off the finished floor surface.

If it were me, I’d want to be careful with any slope and making sure I didn’t create any water issues - I’d first look into the epoxy and if that didn't seem like an option I would paint/stencil it (very careful prep and using the right materials) but admittedly I am not a fan of tile

None of the craft epoxies are exterior rated. You wouldn't get a single season out of that. Porch and floor paint might get you 2 seasons. The big issue is the building itself, not the covering. If they aren't going to do a special assessment to raise the height of the guards, then you aren't really going to put anything over the concrete other than some outdoor carpet like was there. But outdoor carpet comes in a lot better looking stuff than grass or the gray stuff on boats. Get yourself to a commercial flooring store source that sells to commercial accounts.

Stanton Carpet | Indoor / Outdoor