service area on maps shows a red outline covering half of europe

Also worth knowing, the service area outline doesn't really extend your reach. You still rank mostly around your actual address, so adding towns further out won't make you show up there. Google caps it at 20 areas anyway. If you want visibility in outlying towns, a page on your site for each area you genuinely serve does more.

You've probably got a country or a big region in the service area list. Google draws the outline around everything you add, so one country entry is enough to cover a huge chunk of the map. Go into the profile, edit service areas, remove the broad one and add the actual cities or districts you cover instead. Google's guidance is to keep it within roughly two hours' drive of where you're based, and too wide an area can hurt you rather than help.