A 2wd driveshaft has a slip-yoke at the transmission. It does not have flanges at either end, or the double-cardon joint, or the slip-joint like a 4wd driveshaft does.
Lengthening a driveshaft, is a job for someone that has the tools and skill to do it properly. A driveline shop will have those tools and skills to make sure the yokes are in phase, and can balance the driveshaft after lengthening it.
Sorry to see the damage to your 4Runner.