There probably is a suitable replacement electric pump that properly installed, would supply all the volume and pressure flow needed. I'm sure this has been done, but by who, where and if documented I can't tell you.
Many years ago, when I was helping to R&R our family's 1966 Cooper S, we were at once befuddled and annoyed at the lousy SU fuel pump; and, like many here, were not flush with cash to go out and buy what was then the expensive and hard to get replacement. We did a little bit of research and ended up with a nice, made in the USA Stewart-Warner pump, augmented by a small fuel pressure regulator. The combo was much better in quality than the SU, a lot less costly, too.
In our world today, the Bosch pump is, in a couple of words, incredibly expensive with general retail going in the $600-$700 range. That's the bad news; the good news is the quality is excellent. Most people forced to work with their fuel pumps giving them issues are not trying to repair something a few years old, but a few decades old. As I mentioned in the last post, one of these new (properly maintained by using it!) will probably outlive all of us now. Except young Louis of course.
Summit Racing has a good selection for those willing or wishing to pursue it. You just need to look for the right balance of pressure and flow. Their Carter universal, at about $82, does 1.2 gpm at 6 psi; their own brand does .71 rpm but at 45 psi. They offer 325 electric, external fuel pumps, many of them in the $100 range. Surely one or more of those with a pressure regulator would work. Best to know the fuel pump requirements before searching!