Depends what you mean by “connect.” 
You’d need some kind of radio, and which one would then determine the available integration options. And of course older solutions like ST_anything are Groovy-based, I don’t know if there are any plans to move that to an Edge Driver.
[DEPRECATED] ST_Anything - Arduino/ESP8266/ESP32
Why don’t you take a look at the work TAustin has been doing?
https://community.smartthings.com/tag/edge_misc
But you’ll still hit some ST limitations.
This:
gave me the option to customize and tinker to fit everything to my needs if I needed it
Just isn’t a match to ST.
Also, I’m unclear on your comment about Hubitat. It works with more noncloud devices than ST, not less. Such as Lutron Picos. But it’s a local system, not cloud based, so cloud to cloud integrations get complicated.
But again, only you can decide what gives you the best value.