Cancel culture's ending? Heartless construct (5)
I believe the answer is:
erase
'cancel culture's' is the definition.
'erase' can be an answer for 'cancel' (erasing is a kind of cancelling). I'm not sure about the 'culture's' bit.
'ending? heartless construct' is the wordplay.
'ending?' becomes 'e' (this could be a standard abbreviation I've not previously seen).
'heartless' means to remove the middle letters.
'construct' becomes 'raise' (raising is a kind of constructing).
'raise' with its middle taken out is 'rase'.
'e'+'rase'='ERASE'
(Other definitions for erase that I've seen before include "To remove all trace" , "Clear" , "Kill" , "Eradicate" , "Scratch" .)