Should you ever apply for middle office roles like Risk or Operations if your goal is PM at a top HF?

Be careful in doing so. Dont stay around a fund for more than 1.5-2 yrs if no conversation of you moving up....can get jerked around very easily

PM if youd like

I don't think I could ever put myself in that kind of role, knowing I want to actually invest. Besides networking, what kind of applicable skills do you expect to gain from an ops jobs?

It's easier than people may think to get pigeonholed in a particular role, especially if a company's culture is set that way. Networking is a huge plus, but there are also many ways to network outside the company if you start small.

most PMs come from Industry where they learned their business - start there

You might have more luck looking into long-only equity funds. I know a handful of people at that sort of firm who moved up from ops, to equity trading roles, then to the PM team over maybe 10-12 years? All gaining their CFA between ops-trader.

I would assume that it comes down to the specific firm and if they're open to that sort of thing.