Again not entirely sure this is where I should put this question, so please let me know if not.
The house we're moving into (built in 1968, renovated sometime after that) has this strange texturing added onto the walls in the dining room. It's very thick and raised, and has the look of brushed cement, or something similar? We tried sanding it off, to no avail. (Here's some pictures.)
https://i.gyazo.com/2151dde5a3572951...da59ff755c.jpg
https://i.gyazo.com/141d283db2da2bb2...32355acc02.jpg

Sanding, grinding, water, 2 different kinds of latex remover didn't work. It really seems like cement, but it's yellow and has flecks of something shiny, like fiberglass? Sorry, I'm kind of clueless about this stuff.

This part of the wall we ended up having to coat over to move in, but there's still three walls with this texturing. If anyone knows what this treatment is, or how to remove it without having to resort to coating the rest of the walls with drywall mud, please let me know!

 

Just a Guess, Drylok.
UGL | DRYLOK® Masonry Products
Looks like there's been some mold issues going on there.

 

Looks like it might be sand texture. If sanding/scraping doesn't work about the only option left would be to skim coat over it.

 

I'm not sure how you think you're going to avoid drywall mud even if you get this mostly removed.