Being in a small company is different, but not worse (or better). With the roles you have on your plate already, you have a sprawling blank canvas to work from, and in a small company environment, you tend to have a significant amount of flexibility so long as you don’t take your eye off of the main company objectives (vs a large company where “that’s not your department” situations can squash many learning opportunities).
First, figure out what areas you want to focus on. This doesn’t need to be forever, but you are going to need some degree of focus or you’ll risk doing a hundred things poorly and not really learning much.
Once you’ve figured out what you want to focus on first and have done some basic research/discovery, seek a mentor. This is one place where small companies make things harder, as you almost always need to look outside to find mentoring.
With the Project Management and Cloud Architecture bits of your role, you can look at Financial Operations. Just make sure you take a high level look first to see if there’s sense in that (make sure the ROI on you and your co-workers time plus any new services/providers needed makes sense for what you can potentially save - you want to be able to show that your time was well spent with any self-initiated project or you risk someone deciding that you need to be more closely monitored in the future).