If referring to my particular Cosmo, it has never been bent in any situation, nor dropped, knocked, sat on, or even kept in a tight pocket (when carrying it, I keep it in my shirt pocket, inside the Gemini slipcase - as my Cosmo slipcase still hasn't arrived).
IMO, you will be sorely disappointed by the quality and usefulness of the slipcase. In my case, relying on the slipcase caused more damage than it prevented. Once you've slid the phone in and out a few times, the case no longer grips the phone very well. In my case, I pulled the phone (in its case) out of my pocket. Case was upside down in my pocket for some reason. As the case came out of my pocket, the phone slid out and hit the driveway. Now the two back corners are damaged on either side of the hinge.
Personally, I think the case is worthless - a waste of money and yet another layer making the phone awkward to use while on the go.
Ouch, a case that drops the phone instead of holding it, certainly doesn't sound right, so yeah, I can see why you're less than impressed with it.
Anyway, three days ago, my Cosmo slipcase
finally arrived, just one day short of four months, since it was supposedly sent from HK. Either covid-19 has that much of an impact on shipping times or, maybe, Planet should look for another logistics partner. Getting an email about an untracked letter being sent in early April and then nothing for next to four months, until I got a notice from Swedish customs requesting VAT, an import fee and VAT on the fee (because Sweden) for something from a company still within the EU, isn't such a great delivery experience. But, well, now it's here.
Since leather stretches a bit, making a slipcase with just the right friction fit, must be quite tricky, and might be a bit hit and miss. My Gemini slipcase was
very tight at first, but with some use it loosened up to "about right" and stayed that way. I used it every day, first with my Gemini and then with my Cosmo, and it never got too loose. Since it is a tad short, it still failed to protect my Gemini, the one time I dropped it (inside its case), as the device, and not the case, hit the ground first. Luckily I got away with a minor cosmetic dent.
So far, I'm quite pleased with my Cosmo slipcase and I have no complaints about the quality. In my experience, "low quality", often tends to be "uneven quality", so maybe I just got lucky. I mean, I've owned a few Thermos brand vacuum flasks, which were ok, and then I have this really cheap knockoff, that somehow manages to be better. That just has to be luck.
The Cosmo case was also
very tight at first, but now it, too, has loosened up some, and is about as snug as my Gemini case. Time will tell if it'll remain like that. I like that the Cosmo slipcase is a tad longer than the device, though whether that would actually protect the corners of the device, in case of a fall, would probably depend on exactly how it fell. Let's hope I don't need to find out.
I can understand that "yet another layer" can feel awkward. I used to keep my previous phone inside a calendar cover ($1 on a fleamarket) that just happened to be a the right size. It was a two-step process to get the phone out and as the cover was lined with slippery fabric, I had to be quite careful with my smooth-as-a-pebble all-glass phone. Compared to that, the slipcase is easier to use, but offers less protection.