Hello, I can't tell you more than you already know about the Cosmiq algorithm, because it is proprietary and I have not put in the work to reverse engineer it. But, I will say that my experience with it is pretty consistent with yours.
I bought a Cosmiq as my first dive computer, and dived it a few dozen times alongside handful of consistent buddies. Between my main buddies, they were diving Aqualung i300C, Aqualung i450T, Shearwater Perdix, and Suunto Vyper Novo. On every occasion that an NDL was approached, it was my Cosmiq, which I configured in Progressive mode. I never exceed the NDL, but I distinctly recall a dive where we ascended from 95 feet when my Cosmiq reached an NDL of 2 minutes, and my buddy's Aqualung had 15 minutes. This was the second dive of the day, both dives on 32%.
After about 50 dives on the Cosmiq, I picked up a used Shearwater Teric, which I now use as my main dive computer. I still bring the Cosmiq along as a backup, but I leave it topside. I haven't had a failure on my Teric, but I have used the Cosmiq once when I left the Teric at home, and have lent it out a couple of times.
A friend of mine asked if I would recommend the Cosmiq. I told him no, it's too conservative and too annoying to use, and recommended a Shearwater Peregrine instead -- not having a proprietary, super-conservative algorithm is a big part of that. I stand by that recommendation, because he really likes his Peregrine. It does cost more though. At the price point of the Cosmiq, the Deep6 Excursion has a good reputation here, but I have not used one myself, so cannot speak to direct experience.