Nofollow's are still relevant. If 100% of your backlinks are dofollow, then that's going to look unnatural, and you will be more likely to receive a Google penalty.

Nofollow links aren't going to pump up your stats, but they are vital to diversifying your backlink profile.

Ahrefs goes into a lot more detail here: https://ahrefs.com/blog/nofollow-links/