Concrete is a giant sponge. Water will wick through it to the wood framing and destroy it. "Sealing" concrete doesn't do a thing to make it suitable for use as a shower. If you want a concrete look shower, it has to be recessed during the slab pour. Then you build up the preslope properly with mud, waterproof it, and then top it with microcement. That's one of the most expensive options that you can do. Otherwise, you accept that a conventional install with concrete look tile. That is the cheapest way of accomplishing that, and with a curb. Lots of great looking concrete look porcelain out there.

Emser Citizen concrete-look porcelain tile might be a good solution.

Also consider one of the Kohler cast iron shower bases in Dune color. I have the Salient.

The only time an actual concrete slab works for a shower floor is when it’s poured originally with the slope formed in it, for an exterior grade camp type shower. All the rest of the building materials will be block or pressure treated wood. Yes, it will get gunk in and on it, because it is highly porous. And you can etch it with a lot of commonly used bath cleaning chemicals.

Concrete is basically the equivalent of man made marble in how it wears and chemically reacts with humans living on it. That’s why so many people are disappointed with their stained concrete floors or counters. You have to spend a whole lot of money to make unnatural concrete with micro toppings, or industrial forklift traffic grade epoxy coatings, to get a usable wearable surface. Otherwise, it is a really ugly stained garage floor that the stain peels off, gets scratched off, etc.

If you want no frills, buy a shower pan.

To end up with the industrial look, you have to plan for that from the beginning. The beginning is the plan, with all the measurements. Then the slab gets poured with a recess to do that later. Of course you need a proper build up and waterproofing and topping. It costs more than tile.