Hello,
I’ve been using manjaro gnome for the last year and use it exclusively. I recently bought a amd 6600xt video card and it run ff14 perfectly but the junction temp hits 95C. I can clearly see the fans on the video card just slowly rotating and I need software installed so I can manually change the fan speeds. Problem is on AMD website there is no support for anything arch linux. I’m not technical at all with manjaro, but I’ve never had to be. Any suggestions? I have installed the radeon software from pacman but it doesn’t find my video card and the options just stay blank. Any suggestions?
What kernel are you using? Did you try a more recent kernel to see if the same behavior occurs?
Give output of inxi -Fazy
Also maybe it is normal junction temperature. What is the temperature of GPU (not junction)?
//EDIT: yep probably normal ASRock Radeon RX 6600 XT Phantom Gaming D Review - Best Overclocker, Best Cooler - Temperatures & Fan Noise | TechPowerUp
//EDIT2: also you could try at your own risk CoreCtrl program, it seems you can have GPU fan control besides all the other advanced features. AMD GPUs · Wiki · CoreCtrl / CoreCtrl · GitLab
Welcome to the forum! 
AMD video drivers are already included in the kernel, there’s nothing additional to install. Since you have a newer card, amdgpu would be in use.
Which software? There is nothing official available from AMD.
Please post your system info as outlined here:
Try amdgpu-fan from AUR.