Possibly Morgan's Last Heist

Morgan, A D tier villain in capital city, has caught wind of a heist being planned at the lair of Alex, an S tier supervillain.
They are going to get there first.
The mission is deadly, but for Morgan, the prize is much to sweet to turn down.

This is an alternate universe interpretation of how S and D tier might have met. (It was originally potential OU material, but a video posted today by @lighthouseraiders on Tiktok contradicts a small detail halfway through, and I'm to lazy to go back and change it.)