Now it's getting interesting: The well-informed rumour mongers around Mark Gurman now provide a quite credible picture of Apple's M1 successor chips. If these specifications turn out to be true, Apple should indeed be able to offer highly interesting Mac hardware for video editing again in the future.
The only M1 chip available so far has 4 fast, 4 power-saving and a maximum of 8 GPU cores. The latter operate on the level of the best integrated iGPUs from Intel and AMD, but do not come close to the performance of dedicated graphics cards, e.g. in 
Resolve.
However, new Macbook Pros with 14 inch and 16 inch are to be introduced in the summer, which will have a new CPU with iGPU. This is supposed to have 8 fast and only 2 power-saving CPU cores. Ultimately, AMD and Intel are being targeted, which now also offer 8 cores (albeit still with hyperthreading) as the maximum mobile expansion.
However, the iGPU specs sound particularly exciting: Instead of the previous maximum of 8 cores, there will be 16 and 32 cores in future. On paper, this means doubling or even quadrupling the number of cores compared to the M1 chip. But especially in video editing, the GPU memory connection is often a bottleneck, which is why the big question mark lies here. The iGPU has to share the memory with the CPU. However, there should only be a significant leap in performance if Apple also doubles or quadruples the memory interface.
But this could even be the case. The upcoming CPUs are supposed to support up to 64 GB of memory, while the M1 can only address a maximum of 16 GB - with a 128-bit memory interface.
A doubling of the maximum memory often technically also speaks for a doubling of the memory connection. This alone would be a huge performance boost compared to AMD and Intel. And a quadrupling should even reach far into the dedicated mobile GPU market.
AMD's and Intel's mobile answer will be DDR5 memory in 2022, which also offers significantly faster data transfer rates for the iGPUs. But this door should also be open to Apple.
Next year, Apple also plans to introduce CPUs with 16 or 32 fast cores on the desktop (including the Mac Pro), which will then have 64 or 128 iGPU cores. Whether the memory interface would be further upgraded for this can only be speculated. However, memory interfaces over 512 bits have proven to be impractical in the past (HBM aside).
And the extent to which wide memory interfaces and power consumption correlate is another exciting topic in the mobile sector. But we will probably already know much more about where Apple's CPU journey is heading in the autumn...
;)