If the M4 really is coming out in a month, wait. Either get a 25% improvement “for free” (compared to what you’d pay now), or get a used one for cheaper as people with more money than sense rush to upgrade.
But it is way past time to upgrade your Intel Mac to Apple Silicon. The difference is night and day.
Probably have a chance at getting a nice discount on a refurb/discontinued model after the M4 comes out.
At this point wait for the M4, seems like it's going to drop in a month or so, and then get that. Though truth be told you could jump to an M4 MacBook Air and still get better performance than your Intel machine. Most people do not need the "Pro" or "Max" chips, even professionals.
M4 MacBook Air is rumored for next year.
M3 is already a massive improvement, but since prices don’t really get lower as time goes on, you might as well buy the M4 when it is fresh?
I'm still on a M1 max pro, and it was a massive increase. Night and day.