While manjaro makes the machine relatively useful for the current day - for really simple tasks that is, the 13.5 misses much especially with low amount of ram. But worse thing is that this device comes with Intel HD Graphics 3000 and some stuff just simply won't load like Maps because this GPU isn't supported by Metal API.
In the past I tried Lubuntu on eMac G4 with 800mhz PPC - it was a rather painful experience. So I replaced it with 10.4 and with help of Macintosh Garden slapped additionally os 9.2.2 for for some dualboot retro fun