Hey Tom,
Sometime ago I came across the situation with 8.0.30. I noticed is that there is new variable introduced in 8.0.30 innodb_redo_log_capacity and its default value is 100M which is totally half of redo log file which was by default in previous version.
Previous version it was using innodb_log_file_size and innodb_log_files_in_group
something approx 128 * 2 which comes 256M. So consider increasing the size of innodb_redo_log_capacity as the old variables were deprecated from latest 8.0.30.
And yes same was suggested by Mathew as well. Increasing that for some good value will setup your writes better.
set the innodb_redo_log_capacity to at least around 1G because it will try to create 32 redo files like if you set 1G then 1G/32 for each redo log file.
PMM again is best tool for performance monitoring and you should surely consider it to monitor mysql. Let us know how it goes.