Whole house filter/water softener affect water pressure?
Either or both can affect the pressure.
Pressure gauges on both sides would show how much, (if checked while water is flowing through) and in the case of the filter should be there as an indication that it's time to change the filter element. Have you tried that yet? They do require regular replacement (or cleaning, depending on the type of filter element.)
Water softener typically would have less impact, though it's also odd (or frankly poor plumbing layout) to have the hoses on soft water in most cases. Perhaps one specific hose outlet if the water is so hard it leaves spots when you rinse the car, IF you even wash your car at home. Hard water is generally better than softened (with sodium) water for watering plants.
The other element that can commonly affect this is pipe sizes (and/or partially closed valves.) Most water softeners (that I've met) have 1&quot; inlet/outlet, but it's not uncommon for the installer to cheap out and use smaller pipe to connect them, which causes a restriction and pressure drop in use.
It's also possible that the PRV/pressure regulator may be of inadequate size, or have a filter screen of its own that needs to be cleaned. If you have a pressure gauge on it, check to see if it's dropping there (before it even hits the filter and softener) when your water use increases.