Bottom of dishwater filling with water after wash

I would check the filter at the bottom of the dishwasher first of all. There’s a blockage somewhere

Check inside the dishwasher where water is taken away. Then check end of flexi waste pipe for blockage. You definitely have a blockage somewhere due to food. This all builds up over time. I recommend doing a hot wash every now and then to help break down these blockages and keep waste pipe clear. Hope this helps

Could be a number of reasons from blocked filter like the other guy said, pipes not correctly installed, faulty pump etc etc etc

Discharge hose is probably full off debris take it off where it connects to the sink waste and check. I have seen the fittings cut and installed incorrectly narrowing the flow.