Ideas for bonding

I have a location with 2 DSL lines each with statip ip and using pppoe

I also control a data Center mikrotik router and looking for the most efficient way I could do a VPN bonding.
Can bonding be done with l2tp? I know it can be done with EOIP but it’s not very efficient.
Perhaps some way to connect both routers with mpls over pppoe? And use VPLS bonding?