Welcome to Nico!
Your tech has a point about changing CVT fluid more frequently since they are sensitive to used-up fluid.
But every other oil change is bubkis.
I owned 2 CVT cars a Altima and a Maxima, loved them both and especially the mpgs.. CVT fluid interval I think is best at 30,000 miles... anything over 60,000 is asking for trouble IMO no matter what the manual says.
When was the tranny fluid done last?
From a glance, most (if not all) of those codes are transmission codes though.
The Altima as a whole is a reliable car with excellent mpg.., but the transmissions in many model years are a known weak spot.
Best case scenario: The ECU was putting the car in limp mode to protect the tranny since it saw very high tranny tempt readings.. hence the tranny tempt sensor codes.. ..
Worst case scenario: the heat cooked the tranny.. these transmissions are optimized for mpgs and some model years especially, got smaller ATF fluid pumps (to save on energy and mpgs) which in a hot american summer can cause problems... old CVT fluid aggravates this risk by a lot.
Hopefully is just IS the tranny temp sensor as some of the codes suggest... but it may not..
Get it to the most competent shop you have access to (as a misdiagnoses can cost real $$)