>>Narrow fields like these are usually non-controversial.
These were just obvious examples, and you are correct that populist politicians may not primarily campaign specifically on reducing regulation, but they consistently DO mention it in campaigning and consistently do it once in office, because they're usually sponsored by moneyed/corporate interests.
>>"how many soldiers and bases worldwide do we need"..."Should we confront China/Russia or appease it?"
Yes, the populists are consistently gong for appeasement and the "why should we spend money abroad", and opting to allow (or in the 2017-21 admin, actively curry favor with) authoritarians, because populist leaders are almost always authoritarians (whether rightists or leftists), as populist leaders want the simplistic solution of "strongman leaders".
This consistently leads to far worse results within a decade or two. Short term, less is spent overseas. But then the authoritarians make gains and start creating problems that cannot be ignored, and the cost of pushing back has grown far higher. That's the problem with authoritarians; they DGAF about words of concern or condemnation. If they break international law and only get words of condemnation and slap-on-the-wrist sanctions, they read this as approval to go further. Then they do. This is exactly what happened with Putin. He bombed civilians and/or illegally "annexed" territory in Chechnya, Syria, Georgia, Crimea, Donbas, etc. and got no real pushback. So, the thought it would be OK to invade all of Ukraine. This is a rolling disaster for everyone, brought about by failure to push back in earlier administrations (including the 2009-17 admin failing to push back in Syria & Crimea).