Check “Velocity Change”.
Radial impulse without it works kind of like add force, to see effect you would do it with on tick event.
Also check mass of ball. To test if physics works at all move it above ground and enable gravity, if it falls down it is active and physics works.
Also Origin location looks suspicious. Radius of player character collision is 42 units, origin of standard player is 90 units above ground, you add 100 more. This resulting angle is quite steep (75degrees ).
Then you have radius of 200, that may be outside of range. Well its 194.6 so about at max.
And last 500000 is quite big strength.
Ps one more thing, add some printing to this graph so you cansee that event for mouse actually happened, not all blueprints recive input.