The issue of double compression can be resolved by adding a rule to the .htaccess file to disable GZIP only for that specific site. However, this should be seen as a temporary solution. The recommended approach is to optimize OpenLiteSpeed (OLS) directly and use the LiteSpeed Cache plugin, which, when properly configured, delivers outstanding performance and seamless integration with the server.
This is the configuration I use on my own sites, and the results have been very positive. If your .htaccess already contains old or duplicate rules, it may be worth cleaning it up or even creating a new file with only the essentials.