A young man travels onto the astral plane in search of his girlfriend to discover he must battle a demon that has trapped her soul there.

Your revised logline establishes an interesting "Twilight Zone"-like premise, but it lacks the protag's goal and the stakes put forth in your original version, as well as the physical antagonist.

Are you playing around with plot ideas, or do you still plan to have the main throughline of the story be the MC's quest to save his girlfriend from the netherworld demon?

If so, you need to work that back into your logline, because as the revised version reads, the MC's goal appears to be to escape from the astral world to save his own life, with no physical antagonist to threaten him.

HTH

How is this?:

A suspended lawyer meets an enchanting woman in a bar who introduces him to a drug that enables him to astral travel to other worlds for hours at a time. One day he overdoes on the drug and gets trapped in one of them.

Cool idea - sounds like Doctor Strange.

Suggestions:

1. Improve the description of your protag. "A young man" is very generic. A well-chosen adjective and a descriptive noun will make your protag more interesting an appealing.

2. Rearrange your logline so that the timeline of your story flows from beginning to end. You can do this by putting your Inc/Inc first.

"When a novice sorcerer's girlfriend is taken by a malevolent demon, he must traverse the perilous astral plane to find her and save her soul from eternal torment."

Hope this helps - good luck