Calendar App Idea for Legal and Accounting Professionals

Hey everyone. Anyone here know how to build a calendar app that can connect/sync with Outlook and G Suites calendars? I work in the legal and accounting field and the product I sell to them is too robust. A lot of them just need a simple calendar app that can sync with Outlook or G Suites. If you're a developer and would be interested in building this idea with me please dm me. Thanks.