Edit: why the downvotes?
Users on lemmy.world are generally very anti cryptocurrency, they're going to downvote anything discussing the topic. Just browse other cryptocurrency posts in this instance and read all the .world comments.
re: your question I suspect to truly selfhost you'd need to sync the bitcoin blockchain onto your own system and work from there, either with the official client or some other heavy wallet. Beyond that not sure, may need to script a query to your local wallet to monitor for changes to specific BTC addresses (if something doesn't already exist to do this).