For those that don't know Synthocepts are a Titan exotic which increases your melee range. Knockout is a Striker ability that increases your melee range after breaking an enemy shield or reducing them to critical health. I've trying to test this myself and it doesn't seem like it does. Which I suppose would make sense as they probably didn't want Titans flying around the map like Wesker. But it seems really finicky. It can be difficult to judge distances in-game and setting up consistent test scenarios with such a short lived buff like Knockout can be challenging. If anyone one knows the answer for this definitively it'd put my mind at ease.