Getting used to DA/SA takes some practice for sure, but it’s worth it IMO.
Open division allows major power factor scoring, and the guns intended for that division are designed for the higher velocity and pressures of 9mm major (1,320 fps with a 125 gr bullet). I’m not sure the Shadow 2 could handle that long term and is designed for 9mm minor power factor (1,000 fps with a 125 gr bullet). That being the case, you’d be at a scoring disadvantage going up against those guys while shooting minor.
Open division also allows use of a compensator, which would be another disadvantage of shooting a Shadow 2 in Open division (unless you got a threaded barrel and comp). Open also allows magazines that are 170mm in overall length holding 28-30 rnds.
Meanwhile, Carry Optics division only recognizes minor power factor, does not allow a compensator, and allows magazines up to 140mm in length for which there are plenty of manufacturers who make mag extensions that convert a 17 rnd MecGar mag to 23 rnds. The only catch is, the gun must be DA/SA or striker fired.
Embrace the DA! It’s usually only one pull per stage (or sometimes 2 or 3 if shooting a standards ex stage).