No Honor Among Thieves
Get this quest from Merti, Aya's contact in Thebes.
Follow your quest marker to the black market, which becomes an investigation area. You can talk to any of the marked merchants, but the one you want is Siamun, in the bright blue robe.
Follow him into an ambush, because it's always an ambush. In this case, you'll be assaulted by two melee & shield imperials, and one mace-wielding bruiser.
They're in the mid-forties, levelwise, but are otherwise undistinguished. Kill them as normal, then follow your marker to Siamun, who's just hanging out in a nearby alley.
He'll give you the location of a rooftop dice game to the north. There are no guards, but do expect a fight once you arrive.
Approach the game to trigger a cutscene. The moment it ends, the imperial gambler will immediately jump you, and two of his cronies (a giant and a swordsman) will come up the stairs to join the fight.
Technically your objective is to protect Tahemet, but like most NPCs she's effectively immortal- she can be knocked down but not killed. So ignore her for now, and focus on killing your opponents. When they're downed, Tahemet will you give you permission to take the auction invitation from her villa.
Bayek can smash through tower shields, but not wooden doors, so enter via the top floor, then go down the stairs. Here a very mild puzzle awaits you.
A poem on the table elucidates the puzzle, but the solution is to turn the right jackal head once, and the left jackal head twice. This will align the heads with the two jackals facing each other, and human head facing away from the wall. Completing the puzzle opens a passage in the floor.
The underroom here is an investigation area- you can read everything, but the invitation is in the scroll-rack.
Reading the scroll in question completes this quest.