Yes it is more honest. Pretending certainty where you don't have none is lying and pretty often has exact that effect. It is way more egoistic and self centered to act with certainty just so you dont look "defensive" or "timid".
Because then you are exchanging truth for feeling good from appearing strong.
> are you brazenly assuming that people care about how confident you are about things, or are you defensively trying to say the least possible?
This does not make any sense as accusation. You are expressing level of confidence. You can do that independently of whether "people care". It is also perfectly OK to defensively say the least possible. Literally nothing wrong with that.
Aggressively saying maximum, even if you know it is likely half truth at best, is much much worst.
Framing this as a matter of “honesty” is, well reductive.
Your confidence is irrelevant to the discussion, unless there’s some particular reason which makes it relevant. A good reader should not hang much weight on your confidence anyway.