Creating table with primary key constraint name fails when using C# connector

I am using C# (.NET 5.0) and ADO.NET to execute statements on MariaDb. For this, I am using the MySql connector (current version: 8.0.26) to run statements on the database.
I am trying to execute the following statement to create a table that has a primary key. The primary key has a constraint name.

string sql = $@"CREATE TABLE `test` (
`id` INT NOT NULL
, CONSTRAINT `pk1` PRIMARY KEY (`id`)
)";
MySqlCommand cmd = new MySqlCommand(sql, conn);
cmd.ExecuteNonQuery();

Though the table is created, this code throws an exception with MariaDb 10.6.4:
System.NotSupportedException: 'Character set 'utf8mb3' is not supported by .Net Framework.'

It worked fine on MariaDb 10.5.12. When I create named unique and foreign key constraints I don't get an exception.

I am guessing it is related to the switch to utf8mb4 as default collation introduced with 10.6.

See attached file for the full example code in C#.