Basic XAMPP installation for Runway

Sorry to ask for support at such a rudimentary level. Perch installed fine on the local WampServer environment on the workstation at my job, as well as on my employer's web host, but I bought a Runway Developer license for myself and I can't even install it on my own XAMPP server on my Linux (Manjaro/Arch) laptop.

It's a database connection problem, I suspect regard permissions. Both the perchtest and the attempted installation report this:

SQLSTATE[HY000] [1045] Access denied for user 'tdkey'@'localhost' (using password: YES)

I've carefully verified that the password is not incorrect.

In PHPMyAdmin, I gave the database a collation of utf8_general_ci.

These are the permissions I set for the database user, as a screenshot showing the fields I selected in PHPMyAdmin before submitting:

And here is the confirmation message in PHPMyAdmin after submitting the new database user:

Here is how I fill in the perchtest:

The test fails with the reason "We could not connect to the database with the information provided." It shows the SQL (I asssume) error quoted above.

I tried just installing, but that didn't work either. I don't understand the concept of the database prefix, and I've tried both leaving it at its default "perch2_" and changing it to my database identifier with an underscore after it. But I guess that's irrelevant, since the perchtest doesn't have a field for a prefix.