Frr supports two add-path options to send multiple paths to a bgp neighbour:
[no] neighbor <A.B.C.D|X:X::X:X|WORD> addpath-tx-all-paths [no] neighbor <A.B.C.D|X:X::X:X|WORD> addpath-tx-bestpath-per-AS
under vyos these could be represented as follows:
set protocols bgp <asn> neighbor <A.B.C.D|X:X::X:X> address-family ipv4-unicast addpath-tx-all-paths set protocols bgp <asn> neighbor <A.B.C.D|X:X::X:X> address-family ipv4-unicast addpath-tx-bestpath-per-AS set protocols bgp <asn> neighbor <A.B.C.D|X:X::X:X> address-family ipv6-unicast addpath-tx-all-paths set protocols bgp <asn> neighbor <A.B.C.D|X:X::X:X> address-family ipv6-unicast addpath-tx-bestpath-per-AS