$500k cash, $300k loan @2.8%, ~40% LTV. Buy out loan for HELOC?

[Cole Marsteller]

Howdy all. Looking for thoughts on whether I should buy out my loan to have access to more capital via a HELOC or just keep my mortgage and use cash for investing? The mortgage is on a home that is currently my primary residence, but within the next couple years I would like to move and convert it to a vacation rental as it's in a great location. Would this have consequences for the HELOC?

I'm most interested in BRRRR investing so I can pull capital back out and quickly move on to other opportunities.

One concern I have is that it limits my ability to diversify in the future. If for example, assuming I have an empty HELOC, I want to dump a bunch of money into the stock market I would be limited to ~$200k considering HELOCs are not built for LT investing. However allowing me to leverage into other properties while motivating me to pull back out and de-leverage my primary (homesteaded, for now) primary residence feels like hedging against a crash which makes me feel all warm and safe inside.

All opinions welcomed!