Dica testada no Fedora 35.

Primeiro pare o serviço:

sudo service mysqld stop

Instale o mysql-community-test:

sudo dnf install mysql-community-test

Use o modo seguro:

sudo mysqld_safe --skip-grant-tables &

Inicie o MySQL:

mysql
mysql> UPDATE mysql.user SET authentication_string=null WHERE User='root';
mysql> FLUSH PRIVILEGES;
mysql> exit;

De volta ao terminal:

mysql -u root
mysql> ALTER USER 'root'@'localhost' IDENTIFIED WITH caching_sha2_password BY 'novasenha';

Saia:

mysql> quit

Reinicie o MySQL:

sudo kill $(pgrep mysql)
sudo service mysqld restart

Fonte: How to reset the root password in MySQL 8.0.11? - Stack Overflow