For now, those cards will have to wait on the sideline
Modern is the least powerful format where the card is legal, and a five mana artifact that does nothing on its own while empowering weaker synergies is absolutely not good enough for that format
As a result, due to its limited availability and the competitive nature of their distribution, this Zekrom GX promotional card has become a significant find for collectors focused on mega-rare Gen 7 cards or promotional releases tied to official tournament formats
Kefka, Court Mage already gets you some card advantage by hitting play
Unseen Forces is one of the most valuable sets from the EX-era, making it clear why this card commands such a high value
In extreme cases where life isn't an issue, you can even cycle through the entire deck to know your choices and then play knowing what is coming, while in situations where life is precious you can usually get by with minimal loss