on rightclick on entity:
    if name of entity is "[상점] 묘목":
        set {묘목.1} to chest with 6 rows named "&e[상점] 묘목 - 1"
        open {묘목.1} to player
        set {_slot} to 0
        loop 54 times:
            set slot {_slot} of current inventory of player to gray glass
            add 1 to {_slot}
        set slot 10 of current inventory of player to harvestcraft date sapling
        set line 1 of lore of slot 10 of current inventory to "&a[구매가] &f2000원"
        set slot 50 of current inventory of player to nether_star named "다음 2페이지"
            
on inventory click:
    if name of current inventory is "&e[상점] 묘목 - 1":
        cancel event
        if clicked item is nether_star named "다음 2페이지":
            cancel event
        if clicked item is not gray glass or not nether_star named "다음 2페이지":
            if clicked raw slot <= 54:
                if click type is left mouse button:
                    set {_lore} to uncolored line 1 of lore of clicked item
                    replace all "[구매가] " and "원" with "" in {_lore}
                    set {_lore} to {_lore} parsed as integer
                    if player's money < {_lore}:
                        message "&c소지금이 부족합니다."
                    else:
                        set {_item} to clicked item
                        delete lore of {_item}
                        give {_item} to player
                        subtract {_lore} from player's money

or구문으로 다시 시도해보니 유리는 들어오지 않고 네더의 별만 들어오는것을 확인했습니다. 그래서 네더의 별을 눌렀을 때 이벤트가 취소되도록 추가했는데도 여전히 네더의 별이 인벤토리에 들어옵니다..

on rightclick on entity:
    if name of entity is "[상점] 묘목":
        set {묘목.1} to chest with 6 rows named "&e[상점] 묘목 - 1"
        open {묘목.1} to player
        set {_slot} to 0
        loop 54 times:
            set slot {_slot} of current inventory of player to gray glass
            add 1 to {_slot}
        set slot 10 of current inventory of player to harvestcraft date sapling
        set line 1 of lore of slot 10 of current inventory to "&a[구매가] &f2000원"
        set slot 50 of current inventory of player to nether_star named "다음 2페이지"
            
on inventory click:
    if name of current inventory is "&e[상점] 묘목 - 1":
        cancel event
        if clicked item is not gray glass:
            if clicked item is nether_star named "다음 2페이지":
                cancel event
            if clicked raw slot <= 54:
                if click type is left mouse button:
                    set {_lore} to uncolored line 1 of lore of clicked item
                    replace all "[구매가] " and "원" with "" in {_lore}
                    set {_lore} to {_lore} parsed as integer
                    if player's money < {_lore}:
                        message "&c소지금이 부족합니다."
                    else:
                        set {_item} to clicked item
                        delete lore of {_item}
                        give {_item} to player
                        subtract {_lore} from player's money

이렇게도 시도해봤습니다

nether star