Solutionunvalidated
Adjust/remedy the COOP configuration so the iframe/popup context does not enter the 'new with no opener' rule (e.g., relax COOP or ensure same-origin/top-level origin alignment), so window.open will return a window reference instead of null.
c01020f7-2863-4f95-9eeb-532b2aa934e6
Adjust/remedy the COOP configuration so the iframe/popup context does not enter the 'new with no opener' rule (e.g., relax COOP or ensure same-origin/top-level origin alignment), so window.open will return a window reference instead of null.