If Google PlayProtect is enabled it'll be aware of the NewPipe app on the phone or any other Google components may track its usage. Alternatively Youtube could

If Google PlayProtect is enabled it'll be aware of the NewPipe app on the phone or any other Google components may track its usage. Alternatively Youtube could detect the newpipe usage on their end and cross check with the client IP adress collected via the regular YT app. It's certainly possible to detect it.