Hello I fixed this issue with a q-tip with a couple drops of isopropyl alcohol. I rubbed all the battery contacts (even if none is visible) clean which includes inside the little spaces between and air dried the Wiimote for a couple minutes
After I let all the alcohol dry, I used the semi-fresh batteries that I thought the Wiimote drained and they worked again with the amount of life they shouldve had
So, if your Wiimote doesnt respond to batteries or blinks for a few seconds and dies in a minute or a second, this might be the issue and the fix for it