ip6tables-translate -t nat -A POSTROUTING -j MASQUERADE
nft add rule ip6 nat POSTROUTING counter masquerade

ip6tables-translate -t nat -A POSTROUTING -p tcp -j MASQUERADE --to-ports 10
nft add rule ip6 nat POSTROUTING meta l4proto tcp counter masquerade to :10

ip6tables-translate -t nat -A POSTROUTING -p tcp -j MASQUERADE --to-ports 10-20 --random
nft add rule ip6 nat POSTROUTING meta l4proto tcp counter masquerade to :10-20 random