Wasn’t expecting a link to code! That’s awesome.
For now, I’ve been working around it by suspending for the first time when plugged in at the performance state to get it stuck on the highest cap. Using EPP states, it seems to handle power well enough even with a high TDP limit. I haven’t noticed it affect the battery life negatively, at least. I’m seeing 9-10 hours at low usage without any tuning besides the PPD patch, which is better than I expected.