mariadb takes too much load though having sufficient RAM
With your limited information posted, suggestions to consider for your my.cnf [mysqld] section

max_connections=512  # from 2000 because max_used_connections only 213
join_buffer_size=256K  # from 20M to reduce RAM required per connection
read_buffer_size=256K  # from 2M to reduce RAM required per connection
read_rnd_buffer_size=128K  # from 8M to reduce RAM required per connection


These changes will significantly reduce your CPU busy and provide better performance.