So WM changed distrubutor from 1theK (Kakao M) to Sony Music Korea?

Nope, it's like saying JYPE are the Distributors for TWICE Music because they have TWICE's MVs on their main channel and the company is their Label.

Distribution of Music has nothing to with being signed to a Label or Labels rather in this case and many others, Companies will use a 3rd Party to pay for the Expenses for a Song while allowing them to upload MVs as part of the contract.

IF WM actually had money then their music would be on their own YT Channels

Yup they have change theire distributor early this year thats why WM Group songs was not affected by the Spotify/KakaoM issue.

The only good thing about this is most the WM group MVs are now more viewed in their own channel than their distributors channel.