To reduce string tension without changing the string gauge or lower the action??

Try adjusting the truss rod wheel. It will lower the action, but a bit diferently than lowering it by the bridge saddles. It will take some relief out of the neck, reduce neck bow in the middle.

Low tension strings can be bought

But, tension is the same on all guitars in standard tuning, if using the same guage strings. It's a "weight" thing calculated on a string. How much weight needed to stretch the string to a certain pitch.

The only thing is guitar set-up. That's what makes it "easier" to play/bend etc. . . but it is still the exact same "tension" as on other guitars that are equal in tuning/guage.