Useful idiot and paid russian shill are the same thing, in this context.

You're seeing a category difference where there isn't one.

A useful idiot is someone who says/does things X finds helpful.

A paid shill is a person who is paid by X to promote things or ideas.

All of these apply to Timmy Beanboy.

If you... don't believe that Tim Pool was directly paid by Russian Intelligence... you are just factually wrong. That is what happened, he was funded by Russia, the entire thing you describe as a borderline impossible conspiracy theory is... well documented history.

They made up a fake, rich benefactor figure, invented a fake person, and basically catfished Tim and others (Dave Rubin, Ben Johnson) into a financial relationship, where this fake person acted as the pay pig.

Its honestly a pretty common type of scam technique, pig-butchering... but just done in the inverse.