I'm the PM side of this debate with my TL. I've tried meeting him on every level of understanding. Graphs, story telling, Jira issues, business cases, ITIL, OLAs and SLAs, customer interviews, user interviews, you name it. He strongly resists having to justify the things he wants to work on. His justifications are usually some combination of "it's too complicated to explain," and "this code is a mess." Problem is, I need to account for their hours. I need to explain why we're spending money on that thing - to people who are even less likely understand what my TL is saying.

I say this not to diminish your frustration but to appreciate that you tried to meet him at his level, and provide some context for what the other side can feel like.