After you mentioned the theme components, I was able to partially accomplish what I was looking for using the following component: Linkify words in post
It perfectly supports regex so I was whenever someone types mywebsite.com/123/456, it successfully replaces the link with https://mywebsite.com/tag/123-456.
The only thing left is it doesn’t work if someone types the url with prefix https://. It’s still a very nice component though.