Miirym, Sentinel Wyrm
Legendary Creature — Dragon Spirit
Flying, ward 
Whenever another nontoken Dragon you control enters, create a token that's a copy of it, except the token isn't legendary.
Jeff Miracola
Rulings
If the Dragon that entered the battlefield is copying something else as the triggered ability resolves, the token will be a copy of whatever that creature is a copy of.
(wotc • 2022-06-10)
Miirym, Sentinel Wyrm's triggered ability copies the printed values of the Dragon that entered the battlefield. It won't copy any counters on that creature or any effects that have changed its power, toughness, types, color, and so on.
(wotc • 2022-06-10)
Related Cards
Printings
Rulings
If the Dragon that entered the battlefield is copying something else as the triggered ability resolves, the token will be a copy of whatever that creature is a copy of.
(wotc • 2022-06-10)
Miirym, Sentinel Wyrm's triggered ability copies the printed values of the Dragon that entered the battlefield. It won't copy any counters on that creature or any effects that have changed its power, toughness, types, color, and so on.
(wotc • 2022-06-10)