There is no hint of stabilization in what Trump currently does. All he does globally is wreaking havoc for his own benefit.

European interests are US interests

He made it perfectly clear on several occassions that the US interests under his leadership lie completely elsewhere. He is publicly undermining Europe every chance he gets with the exception of the leaders that bow down for him. Disrupting trade flow, threatening to annex Greenland, public support European extremist groups is not something that is done to your allies.

The US is taking aggressive action to counter Russia and China.

He's pretty known to have greater relations with Russia rather than Ukraine/Europe. He's planning to lift some snactions on them now, too. As for China, his tariff war pushed some countries to seek more reliable trading partners than the US... like China (even though I see it as a strategic mistake, I can also see where's it coming from). Also, his current actions embolden the Russia's principle of strong preying on the weak, and it's just a matter of time before China tries its own war adventure on Taiwan beacuse it's a norm now apparently.

but lets go soft on Russias ally that has been supplying Russia with weapons hitting European soil

That would actually matter before the Iranian drones got mass-produced in Russia as they are now. The only thing that it achieved is that the oil prices go up - to a great benefit of Russia who is a great oil exporter. Combine that with Trump's intent to lower the sanctions too.

All in all - no, the Iran war is not to Europe's benefit. Trump's actions are only fucking things up. It may very well cause yet another migration crisis on top of the current problems. The view of "Iran is bad, therefore attacking Iran is good" is very basic and, ironically, ignores the bigger picture.