I stared on a D2 in high school.
Then I got for myself a Durst M600 MF enlarger. This has kept me going for 40 years.
Then I got the bug again. I am in the process of upgrading my setup and building a new darkroom. This time with a 4x5 enlarger.
If you are going back to school, you probably do not have the space for a big or permanent setup. For practicality, I would settle for what you can rig in your new place. My Durst M600 could be packed away into its box between uses, so it was convenient in a small apartment. A friend has her enlarger on a microwave cart, that she can roll into the bathroom. But that cart has to stay someplace when not in use, so it is less convenient for storage than my M600 packed in its box. But it is FASTER to setup and go since it is not packed away, just pull off the dust cover. Trade-offs.
You can rebuild the B66 or upgrade to a C series (for 6x7). Good 50 and 80mm lenses are fairly inexpensive, less than $50 each.