Best practices: which is better for your edge device? A firewall or a router?

Just as the title says... I was wondering if you could eli5 what you thought was best practice for your devices connecting to the ISP.

Would it better to have the ISP - Router - Firewall - L2/L3 switch - Lan.. topology or ISP - Firewall - Router.. etc. Does best practice depend on the size of the company? I haven’t been exposed to many environments so I was wondering what you all thought since most of you do this everyday.

Thanks