Not really moron you do know that Ra has Phoenix mode and Sphere mode right if you seen the tv series you would know that Marik does summon phoenix mode in match with Joey and Sphere mode comes out in the duel with Mia Valentine so Ra is still the best card then Slider can easily trample Obelisk with 5 cards in your hand with Slifers attack.
To be fair, The Winged Dragon of Ra - Sphere Mode is by far the most powerful god card, simply because it's a strong removal card by Tribute Summoning it to the opponent's field.
To be fair the go cards are not good now the sacred beasts can defeat them ah wicked can beat the sacred beasts while the numbers can beat the wicked and the 4 dragons from arc-v can dominate everyone of them odd eyes dark rebellion xyz dragon starving venom and clear wing are currently the best cards
After the summon window has passed, any effects can affect Osiris and Ra.
Obelisk is immune against card effects even after the summon window has passed, but it is only immune to effects that target it. Effects that don't target still can get rid of Obelisk.