Why can i only control my CPU fan once it has started running (I cant start it by myself though)

I have an Acer Predator G3 that is about 6 years old. Except for a new Rx 5700 GPU and a new power adapter everything is original. My CPU gets about 90-100°C hot until the cpu-fan starts blowing (without me doing anything, that means BIOS controlled, so no software or BIOS changes here) at very high speeds. It stops again once the temperature is somewhere below 50°C. Then it heats up again and then it cools again and so on. This is complete bulls***. My BIOS is missing ALL the controls regarding fan speeds (i checked about 10 times). After extensive googling, I have found a programm called argus montior and with it i can control the fan. BUT only if the fan is running already. So I have to let the cpu heat up until the BIOS decides to turn the fan on and cool and once it is running (and the cpu is about 95°C hot) i then can control it. Before I have to buy a new motherboard maybe someone can help me? Why cant i turn on the fan by myself or via argus monitor? why is my BIOS retarded?