/ip firewall address-list add list=bypass-vpn address=domain.com - that’s the simple part. The complicated part is that you cannot use just /ip route rule items any more to define which traffic to send via the L2TP tunnel because these rules cannot match on address lists, so you have to use /ip firewall mangle rules instead to assign the routing-mark (routing table name) and only use the /ip route rule items to prevent the traffic that should use the L2TP tunnel from falling back to routing table main when the L2TP tunnel is down.
/ip firewall mangle
add chain=prerouting src-address=192.168.1.95 dst-address-list=!bypass-vpn action=mark-routing new-routing-mark=via-l2tp
/ip route rule
add routing-mark=via-l2tp action=lookup-only-in-table table=via-l2tp
remove [find where src-address~“192.168.1.95”]
And you have to make sure that the traffic that should go via the L2TP will not be fasttracked, as fasttracking bypasses mangle. So either disable the fasttracking rule completely, or engage connection marks.