I bought Tasha's to get way of mercy subclass on a monk. Only astral self from tcoe shows up, but way of drunken master also shows up from a different book I didn't buy. How do I fix this?
You have probably selected the 2024 Monk class without owning the 2024 Player's Handbook.
If you want to use the 2014 Way of Mercy subclass, you need to select the 2014 Monk class instead. Make sure you have "2014 Core Rules" enabled on the Home tab, then go to the Class tab, remove the 2024 Monk class and add the 2014 Monk class instead; you may need to scroll down to find it.
If you want to use the 2024 version (which is called "Warrior of Mercy") you'll need to purchase the 2024 Player's Handbook.
I bought Tasha's to get way of mercy subclass on a monk. Only astral self from tcoe shows up, but way of drunken master also shows up from a different book I didn't buy. How do I fix this?
You have probably selected the 2024 Monk class without owning the 2024 Player's Handbook.
If you want to use the 2014 Way of Mercy subclass, you need to select the 2014 Monk class instead. Make sure you have "2014 Core Rules" enabled on the Home tab, then go to the Class tab, remove the 2024 Monk class and add the 2014 Monk class instead; you may need to scroll down to find it.
If you want to use the 2024 version (which is called "Warrior of Mercy") you'll need to purchase the 2024 Player's Handbook.
pronouns: he/she/they
Drunken master presumably shows up because the character is in a campaign where content sharing is on.
(Or you bought just the subclass out of xanathar's back when that was still possible, and have forgotten.)