March of Reckless Joy
Instant
As an additional cost to cast this spell, you may exile any number of red cards from your hand. This spell costs 
less to cast for each card exiled this way.
Exile the top X cards of your library. You may play up to two of those cards until the end of your next turn.
Fiona Hsieh
Rulings
You may exile more cards than necessary for March of Reckless Joy's first ability, but you can't reduce the mana it costs to less than {R} this way.
(wotc • 2022-02-18)
The mana value of March of Reckless Joy while it's on the stack is the value chosen for X plus 1, no matter how much mana you actually paid to cast it.
(wotc • 2022-02-18)
You choose which cards that you are playing from exile as you play them, not as March of Reckless Joy is resolving.
(wotc • 2022-02-18)
Rulings
You may exile more cards than necessary for March of Reckless Joy's first ability, but you can't reduce the mana it costs to less than {R} this way.
(wotc • 2022-02-18)
The mana value of March of Reckless Joy while it's on the stack is the value chosen for X plus 1, no matter how much mana you actually paid to cast it.
(wotc • 2022-02-18)
You choose which cards that you are playing from exile as you play them, not as March of Reckless Joy is resolving.
(wotc • 2022-02-18)