Sobek, mage, tank, or both

I know that on the god it says that sobek is a tank, but sometimes his abilities are good at ad.

I want to know if i should build him as a tank, mage, or both, despite how i play

You build Sobek as a tank. Hes almost unkillable if you build him tanky, also you can easily max Magic and Phys damage these days and then still buy Mag-stats, means: If you maxxed all your items you can either go for health if you wanna play as support, or you can go for damage.

Sobek is pretty bad if you build him for huge AP his abilities just don't scale too well I could see him built semi tank with some magic damage something like this :
Wanguard Reinforced Boots VoidStone Warlock Sash Sover/Gia Rod of Tahuti

When I play Brobek I build him almost as a bruiser, leaning more on the tanky side. I wouldnt recommend building full AP, especially high-level games, but if you go straight tank you will find yourself being useful just for tanking towers, setting up kills, and annoying the enemy team.

You have to realize going fully tanky is easy with certain items, try this build:

Mark of the Vanguard, Hand of the Gods, Creeping Curse, 3 Health Potions 2 Mana Potions

Reinforced Boots, Mystical Mark, Void Stone, Ethereal Staff, Warlock's Sash/Sovereignty, sell Mark, get something like Gem of Isolation, or Midguardian Mail, even something like Polynomicon or Divine Ruin

But where is the magical prot in that build? As convenient as it would be for the enemy team to be full physical, 9 out of 10 times that wont be the case. And I personally dont like Ethereal Staff, it costs too much and the AP bonus isnt enough to justify buying it for that, and Gauntlet of Thebes gives more health at full stacks.

Only way in building Sobek in my opinion is tanky. If you build tanky nobody can kill and you can just tail whip and heal yourself and pull enemies and let your team do the rest of the work. Sobek right now is one of the strongest tanks in the game because he has so many ways in staying alive and he can do a lot of damage as well without building him AP or AD. So if you want to play sobek just build him tanky and you will destroy everybody.

And in early game you need to be tanky too if you want to fling your enemies and not die from creeps!