I don't want to sound rude or annoying you, but:
When did you plan to implement the long time functionality of the /jer_profile command.
I mean I look into the mod regulary every 3-6 months and that since years and this feature is still missing.

Currently I am playing modded on 1.18.2 for version context.

+1!!! I love this mod how simply and vanilla like the look. I used back all the time at 1.12 but sadly because this feature missing i can't able to use at 1.16 or 1.18 :/

I do want to re-implement, but I can't really invest the time needed at the moment to learn all the new world gen stuff. Trying to get around to it but just can't find the time :/

How likely is it for the most common ore distributions to have changed since 1.12? cos that's what most people end up using it for I think; the common ore gens like for example mekanism or AE2.

Cos a temporary thing could be, assuming the distributions are still the same as 1.12 and below, adding in an entry using the 1.12 JER to provide a temporary iteration of the profiles, like how you've got vanilla ores already implimented. Though perhaps you'd need to also have a note on each modded ore page saying "Values may be different post 1.12, more accurate profiling is planned for the future".

I can't claim the above will work with 100% certainty, cos I know jack about coding, but it's a potential option xD

Didn't the profiler originally just basically scan already generated chunks and create a distribution profile based on that? I know that would be scuffed and give all naturally occuring blocks a distribution, but as a stopgap solution it might work?