I don't get along with vintage razors. The blade angle thing is probably at the root of it. A two piece razor like a Rockwell 6S or a Timeless seem to make the blade bow and gives me a better shave angle. I suppose if I dedicated myself to using just one vintage razor I would master it eventually but I have razors that work well for me so I stick with them. I do have a Gillette Heritage that uses a head similar to the EJ89 but I get inconsistent results with it. Some shaves are good and some leave me with a sore neck.I had an EJ 89 or whatever they're called that was tough to get a good shave with. Lasted a year and a half before the zamak devoured itself and went to pieces.
Also had a Merkur 1904 that was an average shaver whose zamak also ended it after a year and a half.
I currently have a Gillette Slim Adjustable that I'm trying to get decent shaves with. It's beautiful but honestly not worth anything as a shaver. On 1 it doesn't shave, on 9 the blade angle is nearly horizontal and therefore ineffective yet painful. In between is various variations of useless. Pretty as it is I just don't get along with it- there are too many great razors out there so in the drawer it sits. And to think back in the day guys just got whatever razor was available and suffered through 50 years of it!