Finally sucked it up and replaced our worn out water pressure regulator. Installed a shut off valve as well so I don't have to shut the water off at the meter every time.
The old copper with globs of solder is not mine. Whoever installed the water lines when this house was built should not been allowed near any tools, ever.
Case in point:
They installed the new one in parallel with the old one? That seems like a terrible idea.
The ole "this one leaks so just solder another onto the end" trick.