This is why on greenfield projects I start with an end to end test and do red-green-refactor with it. This lets me defer many architectural decisions (those decisions are usually of a better quality when done during the refactor step) while locking in behavior up front.

Call it what you like. Some people would be insistent that this is TDD. Some would say it isnt because it's not test driven design. Some say it is TFD. I dont really care what it's called, for me it doesnt make sense to develop serious non-spike/non-POC code any other way.

It's one of the few things in tech where my opinion has hardened and not softened over the years.

"Unit tests" on the other hand, blech, sometimes useful, very overused.