Hi,
To build your own Manjaro arm image have a look here
Manjaro arm devices list, I hope more in the future
am6-plus
clockworkpi-a06
edgev
g1-tpc
generic
generic-efi
gsking-x
gt1-ultimate
gtking-pro
halium-9
jetson-nano
m5
nanopc-t4
nanopi-neo-plus2
oc2
oc4
ohc4
om1
on2
on2-plus
opi3-lts
opi4-lts
opi5
opi-800
pbpro
pbpro-bsp
pine64
pine64-lts
pinebook
pine-h64
pinenote
pinephone
pinephonepro
pinetab
pinetab2
quartz64-a
quartz64-b
radxa-zero
radxa-zero2
roc-cc
rock3a
rock64
rockpi4b
rockpi4c
rockpro64
rpi4
rpi4-cutiepi
soquartz-cm4
station-m2
station-m3
stationp1
station-p2
vim1
vim2
vim3
vim3l