Golden-Eyes Green Dragon (trying to make a op card i made as a child playable without losing its essence)

[TMC88]

Golden-Eyes Green Dragon

WIND/********

Dragon/Effect

"Cannot be Special Summoned, except from the GY, and only if it was sent there from the field. Requires 3 Tributes to Normal Summon/Set. This card's original ATK is equal to its Level x 1000. This card's original DEF is equal to its Level x 500. Negate any activated card effect that would make a card leave the field. Any battle damage a player takes from battles involving this card is halved. This card's effects cannot be negated."

ATK:?/DEF:?

 

Originally this monster was a Normal monster with 8000 ATK, what is absurd, but i was a child at that time, then its ok. However i wanted to remake it without changing the ATK, but i know that cannot be a monster with more than 5000 ATK printed on the card, then, since its level is 8, i made it gain ATK equal to its level. After that, i started to think what to do to that 8000 ATK not be a problem. First i made the 3 tributes need, like the egyptian gods, but it is not sufficient. "Armityle" can have 10000 ATK, but only during your turn and is more difficult to summon than this card. Then i decided to make the damage halved, thus making it count as a 4000 ATK monster if direct attack (whose will be ok for the 3 tributes), and the special summon condiction. I made its effects not negable because i do not want that it loses its atk/def because the effects are off, but with a card effect that makes it (or reduce its level) will be ok. For the protection effect, i thinked that something was missing, the card was to simple for a 3 tributes monster (and boss monster of my childhood), then i made that effect based on the my created character that have this card (wich was a good person), protecting everything in the field, even your opponent's cards. Its all, if it still much overpowered and you have a good idea to what to make to resolve this, simple liked or hated it, or (in a not expected case) thinks that it isn't is too powerfull than i think, i'm waiting to know.