That is way too long, for 9GB, I'd expect the import will be done in a much much short time. Then I am not sure, it could be more possible reasons. Maybe you can find a place that has a faster network as a workaround method.
Please use lsphp81-mysqlnd.
Latest mcrypt build is lsphp74, e.g. lsphp74-pecl-mcrypt
So you might want to build the package by following https://docs.litespeedtech.com/lsws/extapp/php/extensions/
For non-rewrite rules, OLS will just bypass it, so you might want to find out what is causing the 500 error first. Does anything show in the error log?