I can also vouch for Biowaves. I got one of their cases for my fairphone 5 and it is really strong.
As the person above said it, putting it on / removing it is really hard, but in exchange it is really strong.
I tripped and felt on a tram stairs slamming the phone to the ground screen first and it survived that without a scrach
I mentioned it a while back in this thread, but taking the biowaves case off the phone is exactly how I broke it (the case, not the phone!), so yeah, be careful there. 
Sorry to dredge back a bit far in this thread; I’m just occasionally on this forum since moving to e/os. The email summaries help keep me a little connected.
For a while, I was frustrated by the effect my Bark case had on microphone reception, and finally decided to take matters into my own hands. Fine woodwork isn’t a skill I’ve kept in practice with, so it isn’t polished or attractive, but I’m happy with the results.
I’ve been on much more of an anti-plastic kick the past year or so, and Bark at least feels like a nice answer to that. Of course, except for the periodic awkward drops, I tend to be fairly gentle with the phone.
I did have one drop that developed a significant split near a top corner, but it didn’t completely separate from the rest of the case. I was visiting family, so I think what they had was Gorilla wood glue, but a bit of careful application of that, making sure it got down into the crack, seems to have worked very well.
