The A14 and M1 have the same building blocks. The M1 just has very slightly higher clock rate, 2 more performance cores and 4 more GPU cores. Unless you're encoding video or something, I doubt you'll notice a difference between the two launching apps, etc.
However, I already have issues with 4GB RAM (plenty of reloads; occasional freezing, lag and crashes). At the same price, I would definitely go for M1+8GB over A14+4GB. I bought an Air 4 last year but if I didn't need TouchID due to face masks, I'd have happily paid the $150 extra for the M1 Pro 11 for my EDC/purse iPad.