I have a TV box with 1.5 GB lpddr3 that has been running Manjaro Arm without any problems for a long time.
I used this TV box to add lpddr3 support to the dram driver many years ago. You can get the latest patch for 6GBIT lpddr3 support here:
https://github.com/iuncuim/manjaro-h616/blob/main/uboot-t98-h2b-lp3/0007-shrink-ram.patch