I have tested the TomoSAR approach here but did not have the required kz file was missing so I could not proceed.
When I was attending the PolInSAR course in 2019, I was told that ALOS data does not have the suitable baseline configuration for TomoSAR, beacause you actually need several images of the same day from suitable angles. Also, the kz file required in the processing has to be generated manually (if not delivered by the data provider, for example of areal campaigns). You can try to create it yourself with GITASAR: SAR image processing for beginners
I hope, I could help a bit by sharing my experience. Please let me know if you make any progress.