MySQL database backup stuck on 'checking permissions'
Rate Per Second = RPS
Suggestions to consider for your my.ini [mysqld] section
innodb_buffer_pool_size=1G  # from 8M for a much better experience
innodb_log_buffer_size=16M  # from 1M to support ~ 30 mn in RAM before write to media
open_files_limit=60000  # from 6209 to better support your opened_* high volume
innodb_open_files=48000  # from 300 to reduce opened_tables RPhr of 24,310
table_open_cache=48000  # from 2000 should always be matched to innodb_open_files
table_definition_cache=6000  # from 1400 to support opened_table_definitions RPhr of 2,152
innodb_io_capacity=1000  # from 200 to use more of your available SSD io capacity

These are just the beginning of tuning for your serious workload.  View profile, Network profile for additional suggestions and free downloadable Utility Scripts to assist with performance tuning.