Transmission oil pump

[Honda-Auto-Journeymen]

So I had a friends boyfriend do an oil change on a 2019 Impreza 2.0 CVT. Instead of draining the oil he drained the transmission and double filled the oil. The car did drive for about a block before going into limp mode. I’ve managed to refill the CVT and drain the oil, and do a complete oil change. I’m not too familiar with Subarus as I don’t work on them often. I cranked the engine over by hand before starting it to make sure it wasn’t hydrolocked which it’s not. Started the car and after idling for about 20 seconds and engaging the transmission it sounds like 2 cats are scraping in a dumpster fire while water is being poured over them. Just looking to see if anyone has any insight. I believe I may be looking at the transmission oil pump, as when I put a stethoscope to the bell housing it is extremely loud, but I’m curious what are the chances it needs a transmission too?
Also I did use all oem fluids during replacement. CVT2 fluid, approximately 4 quarts is what was drained and filled. Approximately 9 quarts of oil was drained.. I refilled with Subaru oil and put in 4.6. Any advice is appreciated.