Adjust board functions (millis...) to a different core clock


I have spent some time on programming with Arduino and for educational aswell as for beginner purposes the Arduino UNO was great. But since my usecases seem to stack and UNOs are pricey I tried to realise some rather simple and small projects using a Nano equivalent. As I then had to realize, the difference in price comes at a cost of quality.

The clock of the equivalent seems to be much lower than the originals. Initially I was trying to digitally controll a WS2812B LED but that wasn´t working. So I tried blinking the boards LED with 500 milliseconds of delay. What was meant to be half a second was rather like 1.5 seconds. I´m not greatly advanced in electronics, nevertheless I concluded the core clock must be slower than the originals, slowing/levering the timing functions (correct me if I´m wrong!).

I´ve searched for solutions in the internet, but they rather discuss overclocking. Still if I had found a fix for that issue, I could try to use it in reverse.

Thank you in advance!