You can shift the range towards lower gears by changing either the size of the rear sprocket, or the front chain ring (or both).
For lower gear range you want either a larger rear sprocket or a smaller front chainring.
If the bike uses a chain, this is simply done with a lot of size options, and adjusting the chain length to match.
If the bike uses a belt instead of a chain, you may have some constraints linked to the fact that there are only a certain number of belt sizes, and when you change the sprocket or chainring size, that creates a change in the belt path length.
Enviolo rear sprocket exist is 22T, 24T, 26T, 28T so if you have something smaller than 28T you have room to go up
Rear Sprockets
www.gatescarbondrive.com
If you can't go up (or up enough) in the rear, you can go down in the front. Front chainring tooth count depend on the Motor fitment.
Front Sprockets
www.gatescarbondrive.com
Another factor is if the bike uses a belt tensioner or not.
I believe Gates has a calculator that can calculate the belt length based on the various dimensions at play.
In order to offer more insights, we would need more details on the bike (chain or belt, front chainring # of teeth, rear sprocket # of teeth, Full suspension or not., wheel adjustment range for belt tension, chainstay length...), and how much lower you want to get.