You must have got cheap blades, my Makita worktop blades are fine. Or
you've got an underpowered jigsaw. Also I use a circular saw run along

Blades were Bosch somethings and the jigsaw is a bosch 6something something.
Seems powerful enough normally.

a batten from the underside of the worktop for straight end cuts, not
had a problem with that method.

In my dreams I own a circular saw...and a workshop and a multitude of other
fun power tools &etc etc

JB