In case you missed it, all links on Mastodon count as 23 characters towards your limit, no matter how many characters the link really is.
So, you don't need to use link shorteners on Mastodon as they won't actually affect the link's length.
Mastodon does this because it's better for everyone's privacy to avoid link shortener services, it means people can see what they're clicking on, and the link won't stop working if the shortener service shuts down.
More info at:
@feditips My random thought on this:
How did the decision land on using 23 characters of the limit for URLs?
Or for that matter, why does any standard emoji (not instance emojis) – like
These are the things that live rent-free in my brain, apparently.