Just letting you know that today I finished an update that adds upload options, including an option you can turn on to “sync removals”, which kindof achieves this.
It may not be the right tool for every scenario though - turning it on basically means that whatever account you upload too will end up identical to the one you downloaded by following/unfollowing and blocking/unblocking as needed. But if you’ve got new follows, blocks, etc. spread across several accounts you wouldn’t want to turn it on or you’d lose all the changes on the accounts except for whichever one you downloaded.
The option works better in scenarios where you’re mostly using a Main account, and just trying to keep the Alt accounts in sync with whatever the Main account does.