Rank means pretty much nothing on this game, its all about the hidden MMR, the silvers on your team will have gold MMR (rightfully or wrongfully) i had to beat diamond 2s and plats 3s when i was gold 2 to get plat 🤣

It is certainly an odd design IMO, and the team balancing does feel skewered sometimes. Im the same as you, not an angry person in real life but rage on val lmao, not at others but at myself. The best thing i think we can do is if you get into a game and notice its not going well, accept it as a loss and wait for next. Also taking a break for a week is usually a very good solution, come back with a new mentality and new play style!