The thing is, Russia has proven to be rather hapless. They have their hands full with Ukraine, and I suspect Ukraine would push them back if they still had support from the US. The EU is slowly stepping up, I just don't know at this point if they can supply arms/ammo to Ukraine fast enough. However, if Russia attacked the UK or Germany, and they really geared up for war, Russia would almost certainly get their ass kicked.
Of course, Russia has a large nuclear arsenal if Putin is that crazy. That would be a big issue if no sane people in Russian would stop him in if he seriously tried to go down that road. But in a 'conventional' war, Russian would have a hard time with any mid sized EU country, and if the rest of NATO stepped up to their treaty obligations (ex-US) that would be more than enough.
Also, per your graph elsewhere, all the Russian bordering states are spending their 2%+ GDP, so if that is Trump's hang up, he would still be obligated to come to their aid. Russia could never leap-frog those countries to attack Spain (for example). Trump is full of BS in general though, so who knows what he might do on any issue in reality.
If you take my words in a very simplistic terms then this is perhaps true. However there are more layers to this.
In other words if Trump wins 2024 who knows what will be on the agenda in 2027. By that time the mess in Ukraine could be long over one way or another and Russia could have another target. Just as it had the next target after mess with Chechens, after attack on Georgia, campaign in Syria ... etc.
Also it doesn't have to be a conventional war that there are problems. Just hitting some pipelines or critical infrastructure is enough to create a mess. However if Russians think that they can get away with it that makes the whole thing tempting.
Regarding Spain: I think you are wrong here. Since Spain is one of the NATO countries that evidently lacks in military spending. So if Russia takes it's fleet from the top of Scandinavia down there and starts to destroy vital infrastructure that could be problem and major economic disruption. As I told you, you think to much in Capitalistic terms. What is kinda wrong logic if you want to understand Russian leadership. Their logic is all about disruptions and hoping to cause disruptions that they can exploit. If you can give 15000 troops for a town like Bakhmut then what is 150 missiles for Spain's vital infrastructure.
Another layer in all of this is preventing the pro Russian politicians from getting elected across Europe.
If you think that everyone in Europe is against Putin then you evidently haven't payed attention. You have obvious people like Orban but there is plenty more. Le Pen was taking money from Putin and never she said something that is truly against him. Plus if the trends continue she could win in next elections. The winner of elections in Netherlands said that he doesn't support Ukraine. Belguim is going to split in two parts as it seem. Pro Russia party is first in Austria (while the next two ones are not too thrilled with Ukraine either). Croatian president says that Crimea will not be Ukraine ever again and that Ukrainians are attention whores with what they are doing. The current deputy prime minister of Italy was walking around with Putin on his T-shit before Feb 2022. What is probably why whole Italy sent only 0.5 billion $ in equipment to Ukraine over the last 2 years. German nationalists see Putin as an ally. The same can be said for pretty much entire Serbian mainstream politics. In Montenegro pro Russian half of the country is even requesting referendum on exist from NATO. Greeks never really severed economic ties with Russia from what I understand (and the place is half dictatorship at this point, with plenty of investemnts from China). For many years Spain wasn't spending even one percent of GDP on defense. New Slovak Prime minister ran literally on stopping aid to Ukraine (and came out first). While during Covid Slovakia was even importing Covid vaccines from Russia, since decent amount of people didn't trust those made by US companies. Turkey isn't really an ally for quite some time, Etc etc.
Therefore as you can see thinking that the Europe will come together against Russia is quite possibly wishful thinking. In other words you as Canadian never came across the narrative that Europe is under US occupation. What in the end comes down to NATO and similar mechanisms in the words of those in Europe that think this way. However this is why Trump's words are actually problematic. Since this signals that he wouldn't be interested in maintaining the status quo that existed in Europe for the last few generations. Not to mention he is personal friend with some of the people mentioned above. His words are actually much more problematic than it seems at the face value.
I know that the people on this forum wouldn't sleep better due to this post but some things have to be said.