Many SEO professionals are saying it is bad to do social bookmarking, but many of them are also saying bookmarking is not bad just do it in proper way.

So what do you think, social bookmarking helps in ranking in 2019?

I think it was not good in 2019.

dsa

Bookmarking is good, just make it to appear natural as much as possible.  If you go and do thousands of bookmarking and expect top ranking in search engines can easily lead to disappointment.