Maybe one way to describe MPLS is its kinda a VPN for VLANs. Or a way to put VLANs in something like a VLAN sorta. I can't speak for them but I worked at what

Maybe one way to describe MPLS is its kinda a VPN for VLANs. Or a way to put VLANs in something like a VLAN sorta. I can't speak for them but I worked at what boils down to a semi competitor a decade ago doing network stuff. MPLS is old stuff now and you can google the specific cisco model numbers and MPLS if you'd like to read configuration guides. Superficially only having 4096 VLAN labels on an ethernet connection appears to be a big problem if you have more than 4096 customers. However MPLS label space is 20 bits so you're good to a million customers. Then you have some "fun" mapping games such that your router connects traffic on MPLS label 123456 (which is your customer number) to local ethernet interface port wtf on vlan 100 or whatever you have been given. At least that would have been cutting edge a decade ago and probably still is today. Its unlikely to be any more, or any less, secure than anything else in a virtualized cloudy environment.