That XL lens is great.
My budget wasn't as high, so I settled for the lower cost 90/f8, rather than the XL 5.6 lens.
Now that you have the lens...go out and shoot.
As others said, shooting is the only way to determine if you need another lens and which lens you might need.
After shooting, you might find out that, as you said, that might be the only lens you need.
Do you have the rest of the kit?
focusing loupe, backs (lots of backs), good tripod, etc.
It took me a LONG time to gradually collect most of the parts of my kit. And I'm still gathering parts; compendium/lens hood, filters, etc.
I brought up the question of price as well, thinking the lens may simply be overkill if all that coverage wasn't going to get used. But the OP has bought it now, and I doubt he would loose a lot of money as it is a very desirable lens. But it is irresponsible not to mention money when a self confessed beginner in large format is enquiring. Clearly the OP knows what he likes in other formats, but just piling in and suggesting expensive options would just be elitist, especially as there aren't an awful lot of bad LF lenses out there, the more expensive options often just do a bit more than others in ways unrelated to outright resolution and application.