Repairing Splitting Baseboard/Trim

An example of the splitting baseboard, it's all horizontal like this

Looking for some comments on how to fix this more for cosmetic reasons. I was wondering if either wood glue/ wood filler would do it, or if some white caulk and then paint would be the best route?

Tried looking for some videos but they all deal with vertical splits. My condo building is from 1893 in Chicago, there was a gut rehab in the 90's. Foundation might be settling more on this sandy soil.

Any tips would be appreciated! (and yes I could google more but getting way too many mixed messages on what to do)