Hi. could I get some feedback on my itinerary. Patagonia in April.
Day 1 Fly to BA-stay 1Night.
Day 2 BA to Ushuaia-Day trips stay 3 night
Day 5 Ushuaia to Punta Arenas and get a car
Day 6 Drive PA to Puerto Natales stay 1N
Day 7 drive to Torres Del Paine stay 2N
Day 9 drive 11 hours to Santiago stay 1N
Day 10 fly Santiago to BA
BA for 3N

I can get an extra 2 days if I need at the beginning but would rather stick to this if I can
Does it look managable? would love to ferry Ushuaia to PA but it's 4 Nights.
appreciate any thoughts

Well just to start, I doubt you can drive from Torres del Paine to Santiago in one day!!!!

You might want to at least have a look at Google Maps.

If you are flying round trip to Buenos Aires I would look into going by land from Torres del Paine to El Calafate airport FTE and flying from there to Buenos Aires.

Seriously, you need to look at a map!

Not sure where you are getting driving from Torres del Paine to Santiago in 11 hours. You could just about do Puerto Montt to Santiago in 11 hours. That one way drop off will be way too expensive. They aren't common as most rental companies are regional and the market is not that big. Leave the car in Punta Arenas and then board a flight for Santiago.