Percona Server for MYSQL 8.0 very slow performance on all myISAM tables

Is quite strange but mysqldump and also alter table to convert to InnoDB are very slow but very very slow. For example converting a table of 5800 rows from myisam to innodb requires about 35 minutes. Server is running on a LXC container proxmox with a ZFS storage. But Innodb Tables on the same server are very fast and doesn’t have any issue.
I have all myISAM variables at default, I didn’t change anything from default but maybe some other conf can make myisam engine very slow.
Also mysqldump of tables to reimport them with innodb engine is very slow.
Anybody had a similar issue?

During the ALTER process, what else is in SHOW PROCESSLIST? What does your CPU/DiskIO look like during the ALTER? Same goes for the mysqldump restore. Sounds like your InnoDB settings might be non-best-practice. Provide your my.cnf