Until year before last, we did ok with squash ... and then came the Great Squash Bug Invasion. I was so disgusted (got one zuke & one yellow) that I gave up and did crazy weird squash last year that was squash bug resistant .... cucuzzi & trombettas. I want to try ‘regular’ squash again this year & see what happens.
Cukes were out of control last year - grew a few plants from seed and had WAY too many ... ended up cutting up pretty much everything coming off the vine and making freezer pickles out of them. If I get cukes this year, will be picking them off the vine at a very small size and making pickles - might let a couple get a little larger for salad fixins’.
I would suspect the most likely problem is nematodes in the soil, as the curcubit family are notoriously impacted by them.
Absent a soil test, I would consider Johnny's method of soil sterilization this summer in a 20 X 20 foot section of tilled soil ,
covered with 6 mil transparent plastic until the soil hits 140 - 160 degrees. That would eliminate nematodes in time for a late summer planting.