By having the phone case consist of two parts one being the sides and one being the back you can make the top and bottom layer count for the back zero, and have your infill pattern show up. You need to orient the parts correctly without changing their location to have a perfect match. If you use honeycomb infill twice by having two back pieces on top of each other you can change the infill "fill angle" and get some cool patterns. For the one in the image you need 90 degrees on one and 118 degrees on other honecomb pattern. Check the images for more info and use my prusaslicer profile if you want.

You can also just not print the back piece and have a bumper case.
I made the fit perfect for my printer, you may need to scale it slightly for yours to fit well.
Holes on the case should be precise as well since I had countless test prints.

I tried printing this with TPU but the results were not satisfactory even after multiple attempts. For some reason the sides don't fit well and start to seperate from the phone.

IMPORTANT EDIT: I realised that having that unique honeycomb pattern by having two infills on top of each other causes overextrusion and messes up with my tolerances and causes all of my issues. I went back to regular honecomb infill and re-adjusted my tolerances accordingly. I tried printing it in PETG this time around and it was too tight so it broke when trying to insert the phone. I then saw someone use PETG and TPU at the same time by switching filaments to add some rigidity to the print. So my new version uses PETG for the first few layers then I switch to TPU to have some give on the side walls. This way I get a perfect fit without the case warping when put on the phone. The new version needs scaling the model about 99.5 percent to have a nice fit on my phone. If you decide to print all of it in PLA or other rigit plastic you will probably need to scale it up to 100.5 percent. Check the newer files for sure I do not recommend going with the old design. The new design may be fine to entirely print in TPU as well but I did not try it.