First, the MX BGP support is only for AutoVPN routes, so it can't be used for this scenario:
https://documentation.meraki.com/MX-Z/Networks_and_Routing/BGP
So assuming you have your own public prefix and public ASN, you are probably going to want to use the 4331 and have it do the BGP for you.
The other alternative is to not use BGP. To simply have each ISP statically route your public prefix down the respective circuit, and to distribute this static prefix into BGP at each of their ends.
Then you can use the MX load balancing option to control which circuit is being used.
https://documentation.meraki.com/MX-Z/Firewall_and_Traffic_Shaping/MX_Load_Balancing_and_Flow_Prefer...
Using the 4331 will give you the most control - by far. I would probably go with the 4331 option if it was me.