Bufferbloat

net.ipv4.tcp_ecn = 1
net.ipv4.tcp_sack = 1
net.ipv4.tcp_dsack = 1

net.ipv4.tcp_congestion_control = bbr
net.core.default_qdisc = fq_codel  # or fq

For the difference between fq_codel and fq, see here.