The all-glass body alarmed me too. It's even more slippery than my last phone - which I didn't think was possible. I was planning on getting a slim transparent cover, but went with my ol' favorite instead - the Poetic Revolution. These cases are butt fugly and will double the weight of your phone, but it'll be indestructible. They're military-grade MIL-STD-810G certified.
I bought the Poetic case which is similar to an Otterbox Defender but slimmer. So far I like it a lot.
https://www.amazon.com/gp/product/B07BHJXSKY/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1