I would also guess electronics. Worn clutches won't act like that. It sounds like it goes into fail safe mode - starting out in a high gear from a dead stop. I have had this in a 93 Passat - turned out it was the trans brain.
Changing the fluid that's in the pan is a drop in the bucket. You want to get more out (usually an auto trans holds as much oil as a 911.
. Many torque converters have a drain bolt, best way to get it all out. Otherwise you may want to have it flushed or do so yourself (disconnecting at the radiator and having a jug of clean fluid on the "in" side and a drain bucket on the "out". This will use a bunch of fluid, but still be cheaper than a pro.
HTH,
George