Some of it depends on which variant fits you best. But yeah, in general the M1 is still very good--if you hear of someone in your circle selling one for cheap because they're upgrading, nab it.

On the variants: An M1 Max is 10 CPU cores with 8 power and 2 efficiency cores.

M4 Max is 16 cores, 12 + 4. So each power core is 50% faster, but it also has 50% more of them. Add in twice as many efficiency cores, that are also faster for less power, plus more memory bandwidth, and it snowballs together.

One nice pseudo-feature of the M1 is that the thermal design of the current MacBook Pro really hasn't changed since then. It was designed with a few generations of headroom in mind, but that means it's very, very hard to make the fans spin on a 16" M1 Max. You have to utilize all CPU/GPU/NPU cores together to even make them move, while an M3 Max is easier to make (slightly) audible.