Partial answer: TCEC Stockfish plays with 43 cores and threads, while the so-called Redfish kitbitzing engine (which is basically Stockfish on stronger hardware) plays with 192 cores and 256 threads. Running at 4x the speed (as measured by nodes per second), Redfish is +50 elo stronger than TCEC Stockfish.
Partial answer #2: Komodo developer Larry Kaufmann writes here that -
Komodo is rated 3423 CCRL Rapid on four cores, but will be playing on a 32 core Threadripper which should boost its Rapid rating to around 3600.
If each core contributes roughly the same to speed, then 32 cores is 8x the speed of the original, and that translates to about 180 elo. (Of course this makes it seem like Komodo scales better than Stockfish, but Stockfish is going from 43 to 192 cores which is much more firmly in the logarithmic part of the curve.)
Partial answer #3: the performance of Komodo 14 drops from +80 elo (2 threads vs 1 thread) to +4 elo (128 threads vs 64 threads). The performance of Stockfish 11 drops from +90 elo (2 threads vs 1 thread) to +14 elo (128 threads vs 64 threads). Source. In this range, the scaling looks pretty linear.