Lovely Plumbing.

brandonf

I don't want to count all the joints.
Crappy water pressure. I have a theory that there may be corrosion buildup inside contributing to it as well

https://youtu.be/xszZCv7DVw4

BenDplumber

First thing to check is the whole house water filter if low
H2o pressure. Either remove or replace filter housing or install a bypass around it. I would invest in a 0 to 200 lb pressure gauge with a garden hose adapter and check at the boiler drain right above the filter

hot_rod

Looks like a Dahl mini ball valve? Some versions have a very small port, that would add some pressure drop. I suppose it could be partially blocked also.