I created a post in the FB group and got a response from Manas, but wanted to put it here (since I just learned that this community existed) in case anyone else stumbled across this..

When using the Ads Manager in GHL and selecting a Sales conversion goal, the conversion events that you select to optimize the ad for should be based on two factors: which dataset you select, and the events associated to that dataset. This is how it works in Facebook's Ads Manager. Currently, even after selecting the dataset, the conversion events list is static and doesn't dynamically update based on the dataset.

Manas ensured me he was raising it with the dev team and they were expecting to look at it after Level Up this year. Until then, I'll just save the money and continue using FB Ads Manager :)