I would enjoy the flowers and then cut it back.

The object is for it to spend it's first year growing roots, not vines and flowers. This makes a huge difference as years go by whether or not you have a scraggly vine with a few blooms or a lush one with hundreds or thousands.

I was hoping to get confessions from those who don't practice best practices. :.)

I don't dig big holes and amend the soil when planting. Though it is controversial these days whether it is a best practice to do so or not.

I planted half a dozen "no prune or light prune" Clematis close to ten years ago. I never pruned them. They had one or two stems and a dozen flowers would have been a big deal. They had bare woody stems for 6' and then some growth at the top only. I babied them. I was afraid to cut below green buds.

Last year I got fed up with the scraggly things and chopped every one of them off. They responded with multiple new stems and hundreds of blooms. They are now much lusher vines but I think it will take a couple more hard prunes to get them to where they should be if I had been pruning properly all along.

I'm never going to not hard prune new Clematis and I'm never going to recommend anyone else not hard prune new Clematis.

It does nothing but good.