I have seen similar concerns raised elsewhere about his goal scoring record.
He's scored 13, 13, 7 and 10 goals for Everton in the league in the seasons so far. xG numbers hovering around 10.
So he's scoring an average number of the chances he gets.
Things get a bit confusing as he's played a number of different roles.
Understat have stats based on positions played, I'm assuming they're reasonably accurate.
His xG numbers are fairly similar across positions. xG90 of around 0.35 for most. 0.49 for FWL. Not entirely sure sure how they distinguish that from AML exactly.
Either way. The goals he's getting, from what's been over these seasons at best an average Everton side are quite good actually.
It seems to me rather rare for wide attackers outside the biggest clubs to get better numbers than that. We've seen several examples of players moving from average to good teams in those roles increasing their goal output significantly.
It's really difficult to score more than that playing in a wide role for an average or poor team. I'm not sure what an average goal return is from those areas for teams outside the top. But I'd say it's quite a lot lower.