Still not draining?

I noticed a few days ago that our dishwasher was not draining fully. I disassembled the sump, etc.–a few bits, but nothing major. The drain hose (internal) appeared to have a small kink, so I repaired that–no change. The entire drain hose was clear, no blockages, and the sink/disposal connection too. I figured that it must be a weakening motor/pump, so acquired a new direct-fit unit (WG04F00655), but STILL no change.

The drain hose is warm and (some) drain water is leaving the unit. The solenoid is functioning (especially as it is now new). The white ball (check valve) is in the tube below the fine particle filter.

What might I be missing here? Many thanks!

Usually, clear clean water that appears in the machine will indicate the water inlet valve is leaking by, and filling with clear water. Dirty/ smelly water usually indicates a drain issue, either with the check valve being worn or stuck, or the drain hose needs to be elevated above where it comes into the sink fitting.
In other words, it has to have a severe rise in the hose to prevent discharge water from bleeding back down the line. This can be done with zip ties.