The difference in using a good example of a first class enlarging lens by any of major manufacturer is almost certain to be less than the difference that one will get between a open frame vs glass negative carrier. Typically, good examples of modern lenses are unlikely to be challenged by the information that a photographer is able to put on a negative when used at optimum aperture.

I would advise you to procure a professional grade lens made by either Schneider, Rodenstock or Nikon from a source that will allow you some time to test it and to return it should you find fault with it. Buying a extremely clean used enlarging lens these days can make a lot of financial sense. The difference in cost between a new enlarging lens and a used one can buy quite a lot of photo paper. If you find fault with the images projected by the lens make certain that the cause is the lens and not the enlarger's conditiion. If you can get you hands on the book Post Exposure by Ctein he has much to say about lenses, enlargers, light sources etc. Particularly useful to you may be the results from enlarging lens tests he has performed and instructions on how to perform such test on your own. The lens tests, perhaps, maybe somewhat out of date since products are continually evolving and these changes may not always involve a name or model change.

If your tendency is obsess over having the best than perhaps you will feel some comfort in buying whatever is the most expensive so that you stop
worrying about it. Then you can concentrate on making some prints to satisfy your spirit.

The skill displayed in using your enlarger and its lens will be, in my opinion, far more important than the difference in between first rate lenses available from todays marketplace.