It has both (now). It's a stretch to say Dynamic columns are on the same level. For example, could you index them with virtual generated columns? The syntax is also not as transparent to applications as the ->> JSON operator.
I think Mariadb was there first. I think the format is very similar at the bit level, but the MySQL has nicer API with automatic returning it as text to apps rather than exposing the bits. I dislike json_extract and wish >> worked but it doesn't seem to on my percona server :(
Anyhow, you'll look back when you've got more distance from Oracle and realize that you don't need to try and convince yourself that MySQL was better quite so hard ;)
I wish we could be more civil and not resort to petty insults. Is there anything I wrote you can dispute with a source?