I get so sick and tired of hearing developers (not you, you get it) whine about tech debt like it's this catastrophe to plan or it takes massive ignorance or whatever.
It's not *just* "we all make mistakes". It's not *just* "we don't have the financial runway to triple the initial development timeline in order to build things right". It's, as you point out, "we don't know what we're building yet"!
Tech debt is fine. Just acknowledge and own it and fix it when it's appropriate. My view is, addressing tech debt before you need to or have nothing else to do (hahaha) is a very expensive premature optimization.
J.Ja