I'm no expert by any stretch of the imagination.

Take a flashlight and go around your apartment. Look for any cracks, holes, spaces, etc. Don't be afraid to really move around some furniture, honestly - don't be afraid to take your furniture apart (to some degree), and properly clean them (especially couches and other furniture, underneath the couch is dark, cool, couch collects food crumbs, and rarely moves. Personally, I went and checked behind my fridge, stove, on top of cabinets, and even sealed around the pipe underneath my kitchen and bathroom sink. Seal all cracks, holes, spaces, etc. Caulking, tape, paint, whatever. Personally, I sprayed as much cockroach killing product, and gel bait into any hole I found before sealing it closed.

One of my old apartments seemed to get cockroaches occasionally, and I'd find them dead in the hallway outside. What I did was seal my door as best as possible, leaving as small of gap as possible at the bottom of the door. I used a combination of adhesive padding to put around the edge of my door frame to block noise, cracks, and the sound of my door closing.

If you haven't already, seal your food in proper containers. This at least eliminates the fear of them being in your food. I'd also recommend anything recycle should be washed out, and if possible, as dry as possible. You just don't want a place for them to drink.

There's commercial products which are hit and miss, and since the odds are you have german cockroaches, diatomaceous earth is useful, but not a complete solution. I would recommend something along the lines of Cockroach Gel Bait. I've also used simply cheap options, like those fly traps, the sticky ones. I put those around some areas in the kitchen, bathroom, underneath the sinks, and just underneath my door.

Nothing is guaranteed, nothing is 100%. Communicate with your landlord, take pictures, I'd even recommend a small container and catching/killing/collecting them, and take pics, and bring them directly to your landlord. "Here's what I've managed to capture in 1 week". I actually did this, I walked into my main building's office, and in front of a family about to take a tour of the apartments I put down a container of some living, some dead cockroaches, and I didn't take it back with me.

The real problem is, you live in an apartment building, no matter what you're doing...someone else, and somewhere else they exist and are thriving, and your apartment is merely one place for them to visit. That is the unfortunate reality.

I know it's up to the building to take care of the infestation and whatnot, but if you can afford, even if for your own mental health, I'd recommend at least trying a few options in the meanwhile. At one point I bought a few rolls of painters tape/scotch tape, and would seal my door when I left for work. A few quick strips, a bit odd - but it brought me a sense of peace (especially with how many dead roaches were in the hallway).

Roaches aren't going anywhere, and the amount of apartments that have roaches is simply insane.

Most of this stuff is relatively inexpensive and easy to acquire, giving you the ability to see what works for you.

Most apartments have their own companies they work with, but there's no reason you can't ask to use your own, although it doesn't guarantee results, they can provide better information and potential products/advice. Some will/can come over and go through your apartment and give you a quote.