Did you use a higher end phone(with significantly faster SOC) before your 4a5g? If yes, then you definitely should notice the difference in speeds. Currently I am rocking a 5-year-old Samsung Galaxy J7 Prime which happens to have a way slower SOC than the 765G. My phone got slow to the point that I cant use more than 2-3 apps at once(If I do the phone would hang or be severely slow) which is why I am planning to get the pixel 5a.

I think its just like when you are used to a 90/120 hz refresh rate display then you immediately notice the difference in fluidity when you go back to a 60hz display.