[Semi-Update] Need advice/help with bathroom, what's under the vinyl sheet edition

This is a semi-update to my post a couple days ago here.

After getting the subreddit's advice, I decided that I wanted to try and resolve the issue this weekend, if possible. My first step was to see what I was dealing with in terms of the subfloor, so I pulled back the vinyl sheet.

Based on what I read and you guys described, I was expecting a plywood subfloor, likely with water damage. Instead I found this.

While not an expert, it sorta looks like another layer of flooring, either vinyl or linoleum. Is this correct? It makes sense that flippers just slapped a sheet of vinyl over the existing floor because it was the quickest cosmetic fix.

Anyways, my real question is what to do next. I poked this layer with a screwdriver in worrisome spots to see if there was any weakness, but it felt very solid. Does this mean the sub floor is probably alright (perhaps protected by this lower floor layer)?

Is the next step just to pull the top layer vinyl sheet, clean the lower layer with mineral spirits, and then start adding luxury vinyl planks (as u/Nellanaesp mentioned in the old thread)?

TL;DR: It looks like there is another floor layer under my bad floor layer. Can I just rip off the top layer and add a new one, or do I need special preparation or to go deeper down?