To check if it works just use ss -tin, for example:
vyos@r14:~$ ss -tin State Recv-Q Send-Q Local Address:Port Peer Address:Port Process ESTAB 0 0 192.168.122.14:22 192.168.122.1:45446 bbr wscale:7,7 rto:201 rtt:0.103/0.048 ato:40 mss:1448 pmtu:1500 rcvmss:1448 advmss:1448 cwnd:140 ssthresh:138 bytes_sent:126383 bytes_acked:126383 bytes_received:20969 segs_out:2460 segs_in:2592 data_segs_out:2445 data_segs_in:341 bbr:(bw:503652048bps,mrtt:0.018,pacing_gain:1.25,cwnd_gain:2) send 15745242718bps lastsnd:3003449 lastrcv:3005252 lastack:3003448 pacing_rate 623269416bps delivery_rate 503652168bps delivered:2446 app_limited busy:2029ms rcv_space:14600 rcv_ssthresh:64076 minrtt:0.018 snd_wnd:64128 ESTAB 0 36 192.168.122.14:22 192.168.122.1:51320 bbr wscale:7,7 rto:201 rtt:0.427/0.555 ato:40 mss:1448 pmtu:1500 rcvmss:1448 advmss:1448 cwnd:148 ssthresh:136 bytes_sent:1779503 bytes_retrans:68 bytes_acked:1779399 bytes_received:167865 segs_out:12061 segs_in:12088 data_segs_out:11899 data_segs_in:3996 bbr:(bw:530564808bps,mrtt:0.068,pacing_gain:1.25,cwnd_gain:2) send 4015063232bps lastsnd:30 lastrcv:31 lastack:31 pacing_rate 525259160bps delivery_rate 458772272bps delivered:11899 app_limited busy:27667ms unacked:1 retrans:0/1 dsack_dups:1 rcv_rtt:392993 rcv_space:65229 rcv_ssthresh:84348 minrtt:0.024 snd_wnd:1344128 vyos@r14:~$