Hello fin4478, thanks for the suggestion.
I have tried the latest Manjaro Xfce, it's able to boot but it's not able to
start the graphics environment. I have seen that for the Ryzen 7 2700U (my CPU)
there are a few people who are experiencing the same problem iwth Manjaro.
Moreover it starts up with kernel 4.14, which is too old for the Ryzen I think.

Going back to your comment on Linux Mint 19 and the old software, is it
possible in your opinion that the old software is causing a fault in the Kernel
for the amdgpu?