I'm not moving the goalpost. In the beginning I was trying to know what your exact position was to begin with. You didn't make it clear, and you can't blame me for that. And then I've also been trying to explain that mentioning problems that apply to both motions isn't valid.
All the while, I've raised multiple clear serious problems that only arise from being against the motion or "life tenure", which you still haven't addressed, and in some cases how these would be worse outcomes.
Regardless, I'll remain in "good-faith debating" and now address your critiques.
1. Politicization, "election schedule", etc., problems: Yes, these issues only arise from having any term limits. My rebuttal to this, however, is that term limits of ~20 years, or a generation, don't allow for the severity and amount of problems coming from the typical single, 4-year election cycle. These cannot be equated or compared as the same thing. Also, I've raised arguments on how this ~20-year term limit would completely avoid problems that only come from your lifetime tenure position.
2. "Life tenure ensures protection...": Yes, technically, since they would still need to be elected even if it's less often. But even so, that's not necessarily always "better". And, also again, it raises unique problems.
We've established that both scenarios bring problems; the question is which one is "better" overall or creates fewer "bad" outcomes.