I now see your dilemma. You need a 4x5 Press camera with the ability to shoot 120 or 4x5 sheet film? Until you can get yourself a 4x5 enlarger, you can contact print your those 4x5 negatives. See how easy that was?! ;-) Now you need to find the right 4x5 press camera with focus screen, a 120 roll-film back, and a working lens/shutter. Shopping is the fun part. You learn as you go.
PS; I say 4x5 because the 3.25x4.25 and smaller sheet films are getting harder and harder to find. Choices are very limited.
6x9 Technical Camera options . . . (but then again there's the limited film problem)
https://www.cameraeccentric.com/stat...horseman_2.pdf
http://www.bnphoto.org/bnphoto/LFN/C..._Horseman1.htm
https://www.pacificrimcamera.com/rl/02493/02493.pdf
https://pacificrimcamera.com/rl/02491/02491.pdf
I took the Horseman 985 route myself. Also owned a 980 at one time. Both purchased from eBay sellers in Japan. Both excellent cameras. These cameras can use stops and cams. There are plenty of Roll Film holders available. 6x9 (2x3) sheet film holders are around, but harder to find.