He chose Le Soir over Le Pays Réel (an openly fascist pro francophone publication even before the war and occupation) though, which meant very little when most papers eventually became fash mouthpieces. Overall Herge just kinda did what most average people (Herge being a average propagandized Catholic monarchist) have done and likely will always do during a fash takeover of your country (head down and try to not get the gestapo to visit your home a second time). In a tier system of collaboration he’d be in the middle tier imho. Also between either Belgium or France I’d likely stick with the country I’m most familiar with given how both were ripe with “third wave” fanatics, neoliberals, and monarchists that never wanted to accept Marxism and instead go into revisionist death spirals (Henri di Man of the Belgian labor party for instance) and do jolly fash collaboration leading to starvation as the Nazis kinda just plundered whatever they wanted.

tldr: surviving during fash occupation doing propaganda pieces for the Vichy government is a moral death pit and Herge never fully repented (and also said stupid shit about the french resistance), he at a minimum should have faced jail time