Once you get there, it should be smooth sailing
At eight mana each, they're massively overcosted now of course, especially because you have to pay mana each turn to keep them on the board
Regardless of how the permanent phases in and out, an important thing to keep in mind is that the permanent does not move to another zone from the battlefield when it phases out, it just starts being ignored by everything happening in the game
It will be interesting to see how Sword of Once and Future performs as format metagames shift in 2023
Sometimes it will turn something that couldnt attack into an attacker, and I havent even mentioned how good this effect is when you have other Roles and Auras around on your board
Other times, it just handles the Collector Ouphe and Orcish Bowmasters preventing you from going off