Hello mate!
Please, try to enable load-balance for VPN-instance in BGP
bgp 100
ipv4-family vpn-instance VPN-X
maximum load-balancing ibgp 2
Also, for the tunnel, you can select the tunnel selection sequence and number of tunnels to be used.
tunnel-policy LSP
tunnel select-seq cr-lsp lsp gre load-balance-number 2 unmix
System-view
ip vpn-instance VPN-X
ipv4-family
tnl-policy LSP