There are adjustments that could be slightly changed to get the bottom tighter. Verify that it is stopping at the top because it is completely flush, and if you still have a gap at the bottom, that's 'just' an adjustment. Looks like a little handyman skills and patience would be required on the ones with hidden cables, but it can be done. Outside edge to wall seal should be the easiest surface to seal by yourself. You could even use some foam stick-on insulation tape temporarily to stop the water until you get it straightened out.