Unless you keep and breed rare fish, then you don't need to fret over pH, hardness or any of that. The vast majority of aquarium fish will adapt to the vast majority of public water supplies.
Just treat the new water for ammonia, chlorine and chloramine. Once the tank is established (cycled), then set up a sound tank maintenance routine that includes large, weekly water changes and your fish and plants will be fine.
No need to make things complicated.
This type of advice is PRECISELY how so many new hobbyist's wind up with sick,dead fishes.
Keeping fishes that thrive in soft water, in hard,alkaline water, or vice versa,,, is often why the fishes die prematurely.
Most of the common fishes for example Livebearer's,,, will do better in alkaline water over the long haul ,and fair poorly in soft acidic water.
Tetra species ,another common species,,, much prefer softer water.
I agree with you regarding keeping thing's simple,,
Keep those fishes that thrive in hard water in hard water,and keep soft water species in soft water.
How's that for simple?