Maybe it is not a good idea to start a fresh install of Manjaro ARM in the “unstable” branch. It has been relatively easy to downgrade thankfully “not so many” packages after i switched to “testing”. I mean “testing” is probably a better idea, if not “stable”.
The best method to prepare a new SD card is the manjaro-arm-installer which takes a branch name as argument - it defaults to arm-stable as I recall - but using a different branch is as easy as
sudo bash manjaro-arm-installer arm-unstable
I am sorry if i wasn’t clear. I did not use the manjaro-arm-installer as i just found out about its existence. What i did was i downloaded the latest RPI image from manjaro github as i was suggested by a dev from this forum. I am on RPI-5. The image i downloaded and flashed to an sd-card (later migrated to my SSD) came with the “unstable” branch defined as default. It is not a huge problem. Unstable has been quite problem-free for me until the lates chromium upgrade so i wanted to downgrade to “testing” branch. It has been relatively easy and no issues so far. But i guess if i wanted to downgrade to “stable” branch, it would cause a lot of problems.
You are using a developer image if it is on unstable branch - but as there is no recent release images - the second best is the tools used to create the images.
My personal experience with Manjaro is that it is pretty stable no matter the branch you are using.