One thing you can do is report this on Pimoroni’s GitHub Page for the Enviro / Enviro+, in the issues section.
Running i2c detect is a nice quick way to see if its working. If its not turned on / enabled you’ll get an error as soon as you run it. Then see what you get. All zero’s or all the fields full are an indication of an issue.
As far as i2c goes, its a shared bus and can have multiple devices connected. You just can’t have two devices with the same address. Do that an neither one of them will work.