If I change Apple ID, will I lose Apple Music playlists or other Apple purchases?

Here's how you change the email address (Apple ID) you use for your Apple Account while retaining everything in your account:

1. Go to https://appleid.apple.com and sign in.

2. In the Sign-In and Security section, choose Apple ID.

3. Enter the email address that you want to use as your Apple ID.

4. Choose Change Apple ID.

5. If you changed your Apple ID to a third-party email address, check your email for a verification code, then enter the code. Learn what to do if you didn't get the email. --> If you didn't receive your verification or reset email - Apple Support

6. If you use services like iCloud or Messages to share with friends and colleagues, sign in to those services with your updated Apple ID. --> What to do after you change your Apple ID or password - Apple Support

For more details, read the document: "Change your Apple ID" --> Change your Apple ID - Apple Support

See this Apple article: Change your Apple ID ->Change your Apple ID - Apple Support (SG)

• If you no longer use the email address that's associated with your Apple ID, you can change it. You won’t lose access to your contacts, purchases, or other account information.

 Then see this Apple article: What to do after you change your Apple ID or password

What to do after you change your Apple ID or password - Apple Support