Palmer is no where near being in a full England squad - and we wouldn't want him there. He needs to spend the World Cup working on with Haaland at home and being ready to cover for any players that come back exhausted/injured.
So far, he has had some nice bits of experience, shown some nice touches and confidence. But in those times there is still no end product - that is fine, it will come. He is playing against beaten, tired teams, so has a chance to play with space and freedom - the next step in his development is to start a match and make significant contributions.
So far he has played in 19 first team matches, and totalled 550 minutes (
https://www.transfermarkt.co.uk/cole-palmer/leistungsdaten/spieler/568177/plus/0?saison=2022)
Phil Foden played in 32 matches (1110 minutes) before he started a Premier League match. At the time some claimed the progression was too slow, but we are reaping the rewards now.
So lets not push Palmer on too quickly - or expect too much too soon - Pep knows what he is doing!