First - this is geometry, not convergence.
The reason it's like this is because the position of the projector isn't correct in relation to the screen.
Yes, keystone adjustment will cure it. Yes it will fractionally degrade the image. No, you probably won't notice.
But - if this projector (with which I'm not familiar) has lens shift - use that instead. Or re-work your positioning so you don't need to.
That makes sense, i have it on a high shelf, with quite a bit of vertical lens shift being used. would i be able to tilt the back of the projector slightly so that the image is 'firing' downward allowing me to reduce the lens shift?