There is Bridgy Fed, which bridges accounts over to the other side if they follow the respective Bridgy Fed account on their platform. This is opt-ín though, so you can’t just follow anyone, they need to have followed @ap.brid.gy on Bluesky. To have your interactions bridged you need to follow @[email protected].
If the account you want to follow is not bridged and you are okay with just reading their posts, you can also use a service like RSS Parrot as every Bluesky account also serves as an RSS feed.
Sorry for the late reply, but I wanted to address your question – I think one misunderstanding is: in a sense there are no Bluesky accounts and there are no Frontpage accounts, there are only atproto accounts. Whether you make a post on Bluesky or Frontpage or Whitewind or Smokesignal, all of them get collected in the same repository. Here is a neat atproto browser which can display this, this is the account of Frontpage founder Tom Sherman and you can find all of his collections there: https://atproto-browser.vercel.app/at/tom-sherman.com