Good Morning,
I would do it as @soundofthunder suggested.
I was helped very well here, in the forum to shrink my /root partition and create a separate /home.
Then I reinstalled Manjaro.
As @soundofthunder said:
Save the /home before and restore it later.
All my settings were carried over, everything was as before.
I did this on my notebook while the system was running.
/root partition I shrinkend it to create a new partition.
Content copied into it.
See [Move /home to another partition] (My thread for Move /home to another partition)
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Greetings
Tony