need stick with best list client only - lists becomes invisible otherwie or use multiple npubs each 500 followers max - no other way

diff Q - do u know if phoenixd (not andriod one) use BIP39 with '0/84/0/0 derivation path ? bc1xxxx seqwit format address

Note that you don't need to send a new event for each user you unfollow. If you are using a Twitter clone (the main, most common and most obvious application, but not the only one), then yes, at each click a new list should be generated. But if a tool is designed specifically to mass unfollow users...