Not an imminent threat? Then what's the concern with the Ukraine, then?
And wouldn't it seem prudent to ramp up armament production when you know what the consumption rate of tanks, guns, bullets and shells is over there?

The concern is that it's a violation of international law and the entire Westphalian order for a country like Russia to just invade another country. It's not an imminent threat, because Russia didn't invade NATO itself (much less Germany) - but it's very important that the use of war to seize the territory of another sovereign state be fully punished and (hopefully) reversed.

Of course it's prudent to ramp up armament production, which is why Germany is ramping up armament production. German arms and munitions business is booming (no pun intended) - it's growing like gangbusters these days:

deutschland.de - German arms industry on a growth trajectory

...which, again, is why the EU Commission's hint that they'll be buying tons of weapons from the US is so laughable. It's a growth industry and a reliable source of export revenues for Germany - the government's 100% on board with having that extra military expenditure be made domestically.

Again, it's not unreasonable to ask them to have some level of deployable forces such that it doesn't take 5 years to stick a brigade in another NATO country (which is where they find themselves today).

Why is that not unreasonable? It would take us at least three years to stick an extra tank brigade of similar size into another NATO country. That's how long it would take us to make 100+ more Abrams tanks than are currently in process, starting from the date we placed the order. It would probably take us close to five years to put an extra tank brigade somewhere that wasn't based on existing Abrams hulls that are being repurposed. Germany's got about 200K members serving in their armed forces - they could relocate an existing brigade to another NATO country within a few days. They just can't generate produce an extra 100 tanks in the space of a moment any more than we can.

Except that...we can do both.

We do both. Now. But we do more of sending them financial products in exchange for useful physical things than the reverse. There's benefits to that. Having ready access to lots of physical things that can be used for a wide variety of economically viable activities is a benefit, and those things are often much more useful than the financial products we send them in return (like the bullion of old). Trump's policy is to try to change that balance, and to start getting fewer useful physical things from Europe.