Get something cheap/free first of criagslist and see if it's for you first. Figure out if you want to dish out the money/time/space to print first.
It took me awhile to figure out what I wanted in a machine to get to my current setup that I'm pretty happy with. You say you would like to get to 4x5, but those take up tons of space if you don't have a permanent darkroom it's not practical to drag in and out. I started out on an omega c700, very small and light and does up to 6x7. Gave it away when I got my Bessler 67xl which let me print bigger but I hated the neg carriers. After a year or so I got a lpl 670xl which was missing its base, I cannibalized the Bessler for its large baseboard to use it. I'm very happy with my lpl machine and do all my smaller format printing on it. I ended up finding a durst 4x5 pro when I went to 4x5, but it was also without baseboard but thankfully with the right condensers that I currently use for 6x9 and 4x5. It's been good, but parts such as negative carriers, lens boards, and long lenses etc have made it much more expensive and time consuming than it would have been if I got an omega d2 or something similar.
Build quality on both the durst and lpl are top notch. Had I had more money a dichronic lpl 4550 machine would have been my choice. Just more parts that are still sold and made new.
Other basics, trays, tongs, timers, grain finder, appropriate lenses for formats, safe lights, filters, and easels. Chemicals and papers.Think about how you will light proof the room. Get yourself a darkroom technique book there are tons if you don't have someone to show you the ropes in their darkroom. Good luck, a darkroom is a truly magical thing, I think you will enjoy yours very much.