Not currently. But ArtNet is reasonably similar to sACN which it does output. You might be able to get something working here. you can use a sACN to ArtNet translator OLA does this and is free and runs on the $35 raspberry pi (or a windows machine with some extra work)1) Can Vixen 3 be configured to output ArtNet? There is an Artnet to uDMX application available from ilLUTZminator.de which some sites recommend for use with applications that don't directly support uDMX hardware.
It's fairly significant. I'm not the best one to answer this technically, but from what i understand it's pretty significant task. I think it'd be easier to start with the sACN output module in V3 and make a copy of it tweaking it to work with the ArtNet protocol rather than sACN.2) How big of a challenge is it to port a 2.1 or 2.5 plugin to 3.0? Is it simply a question of changing a few method names or data types, or is it a fundamental change to the way the module works?
This may be your best option at this point. everything else involves spending about the same money to make it work, or involves a lot of work.3) There's always the option to kiss goodbye the $45 spent on a uDMX dongle and just buy a properly supported one...