That sounds like a capital-N alignment Nightmare, so good on you for getting that figured out!

I think it’s less to do with retaining heat than the fact that the lower temperature printing materials like PLA and TPU will readily adhere even to a cold part, so the time in between nozzle passes is irrelevant. You could add to a PLA/TPU print with a layer time of 10 or 15 seconds or, if you prefer, tomorrow. In fact, with the zooty new printers when using PLA they have whole-enclosure forced air cooling to cool the part off as fast as possible to aid with overhangs and bridging, and prevent sagging when printing fast and thus at high(er) temperatures.

As you have observed, TPU has a ridiculously high layer adhesion in exchange for (or more likely, because of) its rotten temperature stability. It’s also very sticky as a result of its thermal properties, which is also why it strings so durn much.