Every enlarging head has its foibles.
Make a gray print without negative but in focus. If you get marbled uneven look, ask yourself if this would be aesthetically acceptable as an overlay to all your prints (because it is there).
You might be able to obtain two cold light heads for a couple hundred dollars, if both work you have a spare. Cold light heads present a "time" challenge, there are compensating timers to solve that or there are strategies (like leaving the light on).
Color heads are going to be diffuse so they make a good choice.