C:\xampp\mysql

[musicmaster]

I installed Xampp in the D:\xmp

Then I tried to run mysqld:

PS D:\xmp\mysql> .\bin\mysqld -uroot
2022-12-15 19:39:11 0 [Note] D:\xmp\mysql\bin\mysqld.exe (mysqld 10.4.27-MariaDB) starting as process 9808 ...
2022-12-15 19:39:11 0 [Warning] Can't create test file c:\xampp\mysql\data\LAPTOP-ABC1234.lower-test
D:\xmp\mysql\bin\mysqld.exe: Can't change dir to 'c:\xampp\mysql\data\' (Errcode: 2 "No such file or directory")
2022-12-15 19:39:11 0 [ERROR] Aborting

Why does Xampp use the default path instead of the data instead of the subdirectory? And how do I fix this?

[Altrea]

Because you are trying to start XAMPPs MariaDB in a way not provided with XAMPP.
XAMPP starts MariaDB with parameter for the config file path.