I have a custom object called "Engagements" on the page layout I have a JavaScript button called "Set Up New Project Number Request", when that button is clicked it takes me to another Engagement record type with pre-populated from the first page layout then I have to fill four fields from picklist values.  Once the fields contain values, I then click another button called "Submit Project Number Request" this will trigger an process to fire that will send an email to our Finance Dept to create the project code number.

What I'm trying to figure out is what would the best option to replace these javascript buttons, Global Actions or through a flow?

Thanks