If you want a 4x5, any color head machine is a diffusion enlarger. Contrast can be controlled with magenta and yellow filtration.
My omega D6 chromega does fine work from 35mm to 4x5, although I had to make /modify a 35mm carrier with a glass top. It is easy to allign and it stays that way.
The D2 also does fine work.
As far as diffusion vs condenser, a neg developed to print on either with #2 paper will look very close. Diffusion does not hide dust on a neg. how could it without obscuring detail? When working with small neg, a condenser will show a little more prominent grain but the effect is so small that you have to have comparison prints side by side. You can not look at one and say it is diffusion or condenser.
Taking one neg and varying the paper contrast does not give the same result. You must optimise the development for the enlarger and then put the prints side by side. Then you will be hard put to see the difference.
All that being said, I use a Focomat Ic for 35mm and the V35 sometimes. For 4x5 usually I pick the D2 over the color head D6. All color is done on the V35 and and Chromega.
It is all in the lens. That is where the money needs to go. Then a well alligned enlarger. The rest is all your skill.