Templates and general startup advice

Hi everyone. I’m just getting started with Bubble and will hopefully be able to contribute to the community once I have more experience of the platform (my main experience is accounting/tax/SQL). I’m looking to start with a template to save some time but before I take the plunge I wanted to get recommendations on templates. I’m creating a webapp for Accountants to input data, which will then need fairly basic calcs before converting to XML and submitting to a government websites (accounting/tax related). Will definitely also need APIs, user management, user payments (gocardless or similar) and security will obviously be important.

The App Backend and Landing template seems to be the best fit to kickoff but does anyone have any other recommendations/thoughts before I buy? I have no doubt I will need paid help at some point so if anyone has done similar feel free to get in touch.

Thanks in advance.