I did my internal tests and can't reproduce it
20K entries applied in 0.20 sec
root@r14:/home/vyos# cat tmp.nft | wc -l 20029 root@r14:/home/vyos# root@r14:/home/vyos# sudo time nft -f tmp.nft real 0m 0.20s user 0m 0.13s sys 0m 0.06s root@r14:/home/vyos#
200K entries in 2 sec
root@r14:/home/vyos# cat tmp.nft | wc -l 200029 root@r14:/home/vyos# root@r14:/home/vyos# sudo nft flush ruleset root@r14:/home/vyos# root@r14:/home/vyos# sudo time nft -f tmp.nft real 0m 1.91s user 0m 1.20s sys 0m 0.70s root@r14:/home/vyos#