1) enlarger lens? Ain't no wide angle enlarger lenses. And because enlarging lenses are optimized for moderate magnifications (seen as taking lenses, 1:10) they're not great at infinity.

2) barrel lens? There are very few fast w/a lenses in barrel for 4x5 and larger formats. Slow ones, yeah, sure. Fast ones, very few. 3"/4.5 Biogons, ex-USAF, yeah, but they're not common. Make an unrefusable offer for the one in my closet. And before you do that, price 75/4.5 Biogons in shutter. They seem to be a little more common than the ex-USAF ones these days.

3) actual w/a lens in shutter. There are f/4.5ers, at least one f/4er. But what format are you shooting? The 53/4 Super Angulon covers 2x3, no more, same is true of the 53/4.5 Biogon.

If you're shooting 4x5 choices at f/4.5 include 65/4.5, 75/4.5 and 90/4.5 Apo Grandagons and the same focal lengths and maximum aperture from Nikon. All more expensive than f/5.6ers and slower.