First post, happy to meet you all!
So… what‘s the closest one can get to Adrenalin on Linux? I don‘t mean drivers obviously, but fan curves, underclocking, fsr and the likes… what software would you recommend (or other means) to achieve that? Thanks :>
Till now I wasn’t able to find an app that is able to do all the things Adrenalin does … 
Welcome to the purple space! 
Hope you enjoy your time here.
Yeah, I know, but are there maybe some for invidual features? I know CoreCTRL and LACT, but I still haven‘t found a nice fps/temperature hud that I can activate anytime (afaik that‘s not possible with Mango… right?).
For monitoring you can use sensors (lm_sensors) if it supports your graphics card.
I can for example see this entry:
amdgpu-pci-0300
Adapter: PCI adapter
vddgfx: 843.00 mV
fan1: 0 RPM (min = 0 RPM, max = 3300 RPM)
edge: +30.0°C (crit = +110.0°C, hyst = -273.1°C)
(emerg = +115.0°C)
junction: +32.0°C (crit = +110.0°C, hyst = -273.1°C)
(emerg = +115.0°C)
mem: +30.0°C (crit = +105.0°C, hyst = -273.1°C)
(emerg = +110.0°C)
PPT: 6.00 W (cap = 186.00 W)
Then this output can be used by a conky or something like it that will output it periodicaly on the screen. It is probably not the best solution.