It really depends :
How out of flat are your floors? Have you taken a 10' straight edge around the room to get the flooring and found the largest difference?
How picky are you, if the floor has some bounce/flex when walking on it is that a deal breaker? The constraints are there to give you a high quality installation.
Glue down won't work if the floor ...
Self levelling low-spots only, and optionally adding plywood to smoothen the rest.
"self levelling" cement is not liquid as you think and you can apply it in patches without worrying that it will run like water. You have some troweling time to work low areas as large as say 5x5 ft.
Pull it. You can probably remove it easily enough that it comes up undamaged for the most part. Save it if you want / put it on CL someone will take it off your hands. Material wise that stuff is $3.50 a sq ft new it is only 1/4" thick and yours has probably been refinished in the last 70 years, probably has some dents and not as thick as it was ...