Fresh from a conference of MPLS providers telling people that only MPLS or Direct Internet Access (over MPLS) is the only possible solution. Its not, SDWAN over 4G works and often is cost effective too. MPLS is expensive and often more expensive than 3G/4G. An SDWAN solution makes a good network out of any bandwidth.
Don’t trust your service provider to be honest here. They have spent billions building overpriced sliced networks (you might call it MPLS) and want you to keep paying.
Note: US mobile networks are some of the highest priced in the world and it may be financially impractical to do this.