@atomicpoet can't really say it's such a hot take...it is basically fact (even if some Commodore fans don't like to hear it 
Like, the original Amiga corp. was founded by the team that designed the Atari 8 bit platform, the architecture design is basically a modernised 16-bit version of the XL computers etc.
But my hot take would be that the Atari ST is NOT the spiritual successor to the C64, but rather the PET/CBM/B-series machines. Although Shiraz Shivji was involved in the C64 design, it seems to me that he leveraged his work on (or took inspiration from) the actual intended CBM successor, the C900, in order to complete the Atari ST so quickly.
From a technical standpoint, I would actually say the spiritual successor to the C64 is the Apple IIGS, owing to the fact that Bob Yannes designed the sound chips in both machines, among other things. How's THAT for a hot take? 