If you are looking at learning CS in a more holistic manner, there’s Path to a free self-taught education in Computer Science!. It’s a list of courses, categorized by topics, which are exactly what a CS undergraduate would learn. It might feel daunting at first, but you can pick any interesting topic and dive in.
I especially recommend CS50P for beginners.
It’s believed that Glassdoor’s business model is to charge companies for removing bad reviews. So how much value can the rating provide is questionable in the first place.
Personally, for big companies, there are always people writing their work experiences on an open platform. For small companies, it’s unlikely to find a relevant review, if any, on Glassdoor anyway. So I never bothered to use it.