This is wonderful, thank you so much!

I’ve been holding off from switching to Android (and getting a GrapheneOS x Pixel phone) because I have 5 years’ worth of messages on Signal on my iPhone… I’ll look into this method for sure

Oooh interesting! Could you please elaborate / share any resources about this?

Even if your Mastodon instance is federated with Threads, you can still block the whole domain from your account. Explanation / walkthrough here: https://mastodon.social/@_elena/113797840274825233