Seeking advice about vinyl vs CD.

Vinyl is healthier.  I have to get off my fat ass and stand up and flip the vinyl.  You want to be healthy don't you?

This question can only be answered by you. What can we add that would change your mind?

Dump  the vinyl side! Keep it!

What other people do should have zero effect on what you should do.
I think, psychologically, if you ask the question, you want to get rid of vinyl.

You have a nice turntable though.

All three reproduction methods create a different ambience and sound. If you have a great well recorded set of classical LPs you are going to get next to nothing for then just put up with the storage and enjoy. CDs (my personal weakness give me something i own enjoy and collect) have better dynamic range than LPs so suit that genre too. Streaming for things you don't have or would maybe like to own? On the end you pays your money and takes your choice - me Id choose all three.

Unless you have very rare, expensive classical LPs, moneywise, it likely is not worth the effort to try to sell them. Better keep them. By the time you may like them more than rock music. Getting older, that at least has been my experience. I primarily now listen to classical and jazz and have started selling my huge rock an pop collection bought in the 60s and 70s. Though I know there are people in their seventies or eighties who still believe that Sgt. Pepper is the best music ever made and listen to it every day,  that's not me.

My tastes are the opposite of the OP.  I listen to Classical about 95% of the time.  I no longer own any physical media that isn’t classical.  If I want a particular pop or jazz album I stream it.  I recommend that he ditch his LPs and stream his occasional Classical listening