Eagle's likely later refit follows an escort-carrier role

What upgrades would HMS Eagle likely receive if she survived beyond 1942?

Probably better radar and 40 mm anti-aircraft guns for a secondary escort-carrier role.

An expensive attempt to turn Eagle into a modern fast fleet carrier is unlikely. Her probable future is an escort or secondary carrier role where an additional flight deck still has value. Better radar would improve awareness and control, while 40 mm guns would strengthen close anti-aircraft defense. The limited refit follows the mission and remaining service life of the old hull rather than chasing the capabilities of a new carrier.