The meteor and Garou vs Boros statements both imply this.
Murata did say "if Tatsumaki were able to pull the meteor from space, she would have been able to bring down
Boros' ship without difficulty"
And if it would be somewhat difficult for Tatsumaki to bring down his ship, that does imply some comparability between Boros and Tatsumaki
Likewise, the Boros vs Garou statement is outdated now that Cosmic Garou exists but if there's any still truth to it would also imply Boros > Orochi
Are you sure the logic of monster attacks increasing on earth in linear fashion applies to Boros? For all we know this dangerous escalation is confined to earth and earth alone, meaning it would have no bearing on how powerful Boros is.