My goal is to at least have positive cash flow while I build equity in the investment property.Has anyone successfully purchased a buy & hold with this strategy?

Generally, here's the rule I follow with stuff like this: If every house on the block has a garage and you remove it from your house, that's an expected facet of the home that is lost and you will objectively lose value when comparing to another house from a "market value" perspective; especially from an appraiser's point of view. 

There is no short cut in building and retaining wealth.

. - When building codes are updated, it is often uneconomical for all buildings to be upgraded to meet new codes.

I'm a new investor (have a separate W2 job), looking to build storage in near future.

It comes from building relationships with anyone who doesn't hang up on you.What's your pitch to them? 

If you're building with a production builder who has an in house lender, essentially they offer 30 year fixed. 

Just to clarify, I’m trying to start building a real estate rental portfolio.

This is called the blanket rule.

Are there specific networking events, online platforms, or strategies that have proven effective for building relationships with investors?