Venom doesn’t exist in the MCU
While Sony made a deal with Marvel to allow for the appearance of Tom Holland’s Spider-Man in both the Sony-run franchise and the MCU, no such deal has been worked out for Venom. What that means is that Venom exists in the same reality as Spider-Man and the Avengers, but not the same cinematic universe. Yeah, your guess is as good as ours here, honestly.