I am using Firefox v. 128.0.3 with iMac v 10.15.7 and it all works perfectly for me - including launching links that auto launch Firefox. No more blank pages!
Same here - Firefox v. 117.0 on iMac with Catalina v. 10.15.7All external links not launching in Firefox - takes another click.This also happened a couple of yeas ago - exactlys same thing and was corrected with another Firefox update.