I also have a 2015 11' MBA, with 8GB and the i7. Still screams along and does everything just fine.What can't your current hardware do? It doesn't sound like you are a very demanding user so why upgrade. I use a 2015 MBA 11" and it still works great, I even run VM on it without problems.
I'm sure people will be saying the same thing about the M1 MBA when its 7 years old.