无法通过用户名直接连接psql？PostgreSQL默认库匹配异常

当执行psql -h localhost -p 5432 -U myuser命令尝试连接时，PostgreSQL会将用户名（myuser）解析为默认数据库名，因此除非同时指定数据库，否则无法继续操作；但使用用户名postgres可以正常访问，原因是存在同名的postgres数据库。

以下是终端操作示例：

MacBook % psql -h localhost -p 5432 -U myuser  
psql: error: connection to server at "localhost" (::1), port 5432 failed: FATAL:  database "myuser" does not exist
MacBook % psql -h localhost -p 5432 -U private 
psql: error: connection to server at "localhost" (::1), port 5432 failed: FATAL:  database "private" does not exist
MacBook % psql -h localhost -p 5432 -U postgres
psql (14.11 (Homebrew))
Type "help" for help.

postgres=# \du
                                   List of roles
 Role name |                         Attributes                         | Member of 
-----------+------------------------------------------------------------+-----------
 myuser    |                                                            | {}
 postgres  | Superuser                                                  | {}
 private   | Superuser, Create role, Create DB, Replication, Bypass RLS | {}

postgres=# \l
                            List of databases
    Name    |  Owner  | Encoding | Collate | Ctype |  Access privileges  
------------+---------+----------+---------+-------+---------------------
 mydatabase | private | UTF8     | C       | C     | =Tc/private        +
            |         |          |         |       | private=CTc/private+
            |         |          |         |       | myuser=CTc/private
 postgres   | private | UTF8     | C       | C     | 
 template0  | private | UTF8     | C       | C     | =c/private         +
            |         |          |         |       | private=CTc/private
 template1  | private | UTF8     | C       | C     | =c/private         +
            |         |          |         |       | private=CTc/private
(4 rows)

postgres=# \q
MacBook % psql -h localhost -p 5432 -U myuser -d mydatabase                          

psql (14.11 (Homebrew))
Type "help" for help.

mydatabase-> \du
                                   List of roles
 Role name |                         Attributes                         | Member of 
-----------+------------------------------------------------------------+-----------
 myuser    |                                                            | {}
 postgres  | Superuser                                                  | {}
 private   | Superuser, Create role, Create DB, Replication, Bypass RLS | {}

版本信息：
PostgreSQL 14.11 (Homebrew) on x86_64-apple-darwin23.2.0，由Apple clang version 15.0.0 (clang-1500.1.0.2.5)编译，64位

已尝试的解决方案及结果：

• 使用private用户连接，结果与myuser相同，因不存在名为private的数据库报错
• 执行postgres=# ALTER ROLE myuser SET search_path TO mydatabase, pg_catalog;修改search_path，无效果
• 重建share/postgresql@14/目录下的pg_hba.conf和postgresql.conf文件（原目录只有示例文件），问题未解决

需求：希望能够通过psql -h localhost -p 5432 -U myuser直接访问数据库，无需添加-d mydatabase参数。

内容的提问来源于stack exchange，提问作者Leo