Year end adjustment: is it worth it if you think you have to do the full tax return?

It’s year-end-adjustment time (年末調整) and I’ve just added up/estimated my interest and dividend income from 2025. Looks like it is a bit over 30万 (something around there). I believe that’s over the limit for simply doing a 年末調整 and letting my employer handle it. I’ll probably have to do my 2025 full return (確定申告) in March.

Is there any reason to submit my 年末調整 anyway? Would it make my return easier to do? Or should I just skip it?
It will be much easier to get the numbers right once December actually happens and I get my reports.