upgrade 20.04 to 21.04. Direct upgrade or from scratch?

I have ubuntu 20.04 and I'm considering upgrading... I remember a few years ago that I tried on another machine, and it just didn't work, I had to reinstall from 0. Then on my next machine I had to use windows and just last year I came back to ubuntu.

Now, it's been a few years since then... it's still an issue or it it safe to upgrade directly?

Thanks