Should my business post on Instagram?

It mostly depends, though the bar for having a presence has dropped. Instagram is now common enough that an empty or abandoned profile reads as a gap, particularly if you recruit, sell to marketing and creative buyers, or have any physical presence. 

A reasonable minimum is a complete profile with a clear bio, a few pinned posts explaining what you actually do, and Reels cut from video you are already producing

Treat it as a credibility surface rather than a lead channel and Instagram can stop seeming expensive and unmanageable.