How to replace soldered valve with push in connect?
Well since you want to use a shark bite you may not like my solution.
I would cut both sides make a U shape. This is how I would sweat in a new valve on the left with a standard sleeve on right , you could do it with shark bites but this is how some plumbers would do it without kinking the copper.
Measure everything so when you push them together they both slip on.
Using copper sweat fittings they can be adjusted before sweating.