Whirlpool WDT730PAHZ0 not draining still

Hi All,
Looking for the next sequence of things to try for my son’s 3yr old dishwasher. All the basics (disposal, hose, filters) have been checked. We’ve replaced the drain pump(not original W10724439 but the W10876537) and the circulation pump(W11612327-purchased from here, thank you!) and yet it is still not draining the bottom. What is next logical thing(s) to inspect, in what order, and how? Are there other types of tests we can do? Tried googling, over and over, but there’s so much generic stuff that keeps popping up.
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Btw, my 20+ yr old Whirlpool is still going without a single part replaced. Go figure. Uh oh, I just jinxed it. lol
Thanks!
Chet

Anyone?