Sorry to read your sad tale. Everyone gets crop failures, but it is truly unfortunate that you have had so many.
I don't know whether its any use, but my advice to newbies is always to grow what they like to eat. If you grow something you are not mad about, and it fails, then that is doubly disappointing. But growing something that you like, that succeeds, and because you harvest it fresh tastes much better than the supermarket, that lifts your spirits and will give you a good base to build on.
I get extremely annoyed when a crop fails. I've been growing veg for donkey's years, so I should know what I am doing, my time is precious, and things have no right to fail! I have clearly blotted it out of my memory, but now I put my mind to it the following did not work last year:
Onions - sets planted overwinter, and the wet did for most of them. Garlic was poor too.
Celery grown for the first time on a whim. Seed sown a month or so late, was a busy time for me, late pricking out, late planting out, never came to anything.
Celeriac - I've grown this often, but last yet I sowed it late and planted out even later. Tasty but the roots were disappointingly small
Main crop spuds - picked up some cheap offer at the garden centre, varieties I had never heard of ... I got what I should have expected, poor results.
Brussels sprouts - rotavated the patch shortly before planting. I know they like rock hard soil, I thought stamping it down would be enough. Result: All sprouts blown and pretty much useless.
Tomatoes - infested with white fly as usual. Even though I grew lots of Marigolds to try to keep them away.
Dwarf French Beans intended as an Autumn greenhouse crop, sown far too late to be any use at all. Started flowering just as the cold weather killed them off.
Christmas spuds. Bought prepared seed potatoes in July, they are still on the window ledge chitting
might actually do OK for this year's crop
Courgettes were a disaster - I convinced myself that they would be fine in the shade of a tree. Were they heck
Parsnips grown in paper pots. Germination was terrible, several re-sowings, thus planted out so late they didn't come to much.
Salsify was mostly rotted in the ground when I harvested it (early Winter). Dunno why.
But the Cucumbers, Leaf beet, Kolh rabi, Sweet corn, Squash, Strawberries, Raspberries, Beans, Cauliflowers, Swede, Early spuds, Mooli radish, Lettuce, Tomatoes, Aubergines, Melons - oh the smell of those Melons! - chillies, beetroot .... they were absolutely fantastic!