My son has an M1 MacBook Air with 8GB memory and 512 GB storage, plus external drives.
After using it for light video editing and Photoshop/Lightroom Classic work, he will tell you that it is capable but not ideal. Once you add titles, transitions, and effects to 4K video tracks, performance bogs down. When the SSD is more than half full, it slows down. So working with a FAST Thunderbolt 3 or 4 external drive (1TB or larger!) is essential for video.
MOST people,
those who do not do video production or heavy photo editing, will be fine with 8GB memory. However, my recommendation is to consider 16GB memory and 1TB storage to be the sweet spot for entry level M1/M2 Macs. My M1 Air is configured that way, and it has plenty of breathing room for simple 4K video editing. Audio is a breeze up to more than 50 tracks, even with complex processing plug-ins. Lightroom and Photoshop still run fine after two years of heavy use.
My other twin has an M1 PRO MacBook Pro with 32GB memory and 1TB storage. It is a very solid machine for video editing in Final Cut Pro, DaVinci Resolve, Adobe Premiere, and for use with Adobe Photography Plan applications. Jay has never complained of any slow downs.
You want 16GB or more memory to avoid the paging/swap memory that Tri-X talked about. You want 1TB storage so that when paging/swapping does occur, you have plenty of space to do it!
There is an old rule of thumb that your computer WILL slow down gradually when the boot drive becomes more than half full. That is certainly a factor in my recommendation to get 1TB storage. You can live in half a TB most of the time, by using external drives for all your data. You're going to need a conventional backup drive for Time Machine, and a two or four terabyte SSD for use as a working drive. Then you should use some larger conventional drives for use as data storage.
One thing to consider about the M1 and M2 series Macs is that the
single core performance of M1, M1 Pro, M1 Max, and M1 Ultra systems is almost exactly the same! The the
single core performance of M2, M2 Pro, M2 Max, and M2 Ultra systems is almost exactly the same! Where the higher level Pro, Max, and Ultra systems shine is in multi-threaded applications that can use more than one processor core, and when processing video or graphics that are supported by the dedicated processors on those chips.
On the M2 machines, AVOID THE BASE *STORAGE* MODELS if your applications are input/output speed dependent. I'm talking to Lightroom Classic and Photoshop users here. UNLIKE the M1, the M2 chip uses just one 256GB RAM chip instead of two 128GB RAM chips configured as a RAID array. So get 512GB or more. On M2 Pro and Max, you'll want 1TB as a minimum, for the same sort of reason: The use of two DRAM chips in a RAID configuration improves speed dramatically for I/O operations.