Who are some of those experts in your opinion? Sounds like an interesting read perhaps.
The Duck of Minerva is a good blog, with contributors who are at the level of full professors at leading universities https://www.duckofminerva.com/
Political Science Quarterly can be fantastic, though being a quarterly, won't be tackling news from the last 24 hours (but I think we have enough of that).
For a different perspective, the Lowy Interpreter blog at Australian think tank The Lowy Institute, has excellent, expert analysis from a often strikingly different geopolitical point of view: https://www.lowyinstitute.org/the-interpreter
Other non-partisan think tanks can be a great source. U of Pennsylvania has a ranking of them which, while I wouldn't take verbatim, can provide a good starting point.
It looks like some of this is that they are professors, or they cite each other, which is rather circular.
Are there testable predictions, or some utility to those who aren't political scientists?
It would be lovely if we had a kind of absolute scale to measure by (as is often done in sports and other less complex domains), but that is not possible. However, what is possible (or should be, to some degree) is that (more) people could think from an absolute perspective, which I believe can substantially change how some things appear.
How you would go about doing this though is not obvious, to me.
Finance, politics, international relations are more complicated because humans play against humans. As an insight becomes known it becomes useless because humans incorporate it into their models to beat other humans.
But Math clearly has real experise. Ramanujan was recognised on the basis of correspondence. Soros has real expertise in finace. Dominic Cummings managed to run two referendum campaigns that beat UK elite opinion. Kissinger and Bismarck are and were real experts in politics. But they can't demonstrate crushing qualitative superiority like experts in exact sciences can.