Anyone remember when "Rejoined" was about creating the first artificial wormhole? These guys had a working, miniaturized version of the tech in an Iron Man suit more than 100 years earlier.
First STABLE artificial wormhole. Stamets explicitly mentions that the microwormholes the RA suit makes are unstable and need a graviton beam to keep them open and tethered.
The Federation artificially made a wormhole back in TMP just by activating a dodgy warp drive.