I see you predicament. The problem there is and I know from experience if you don’t have a RO system I would steer clear of rams and apistos. They are extremely sensitive to ph change. If your tank drops on over the span of time in between w.c. and you do a water change with the 8.8 ph water it’ll wipe um out.
You would also remove all of the trace elements and minerals by boiling it, so you’d have to re-mineralize the water before adding it to the tank.
And like mentioned, pH swings are what will cause your fish problems. Much better to maintain a stable pH than to try and chase an ideal.
Anything wild caught from South America would likely not fair well in a pH of 8.8 – even if they survived the initial acclimation, they likely would not fair well over the course of a year.
If you can get Tank Bred Rams you’d likely be okay. Most likely they’d be hatched using RO water then transferred to tap water once free swimming.