A union in Finland was already asked to support by Swedish unions and they already agreed.

But only regarding stuff exported to Sweden.

Tesla in Finland already follows the agreements agreed by the unions and the employer representative in the so-called kolmikanta. Because it's the law. Sweden has more loose laws there.

Finland had a devastating and bloody civil war with whites and reds and a somewhat different history than Sweden regarding the labor market.

IIRC some Finnish union people have tried to export labor union concepts to say China but I've heard that labor activists are persecuted there.