Hi, please try this:
– apply “medium privacy more compatibility” settings scheme
– set “rename plugins” option to “all plugins” in Permalinks & URLs tab
– enable “Auto Configuration” option in “replace tools” tab
Regarding woocommerce REST API, do these:
– empty out “ajax url” field in Permalinks & URLs tab
– disable/uncheck “Anti Spam” option in General settings tab
– disable/uncheck “Directory List” option in General settings tab
– disable/uncheck “Hide PHP Files” option in General settings tab
– if still the issue, then please try deactivating IDS option in IDS Firewall tab.
Regarding slow site speed, it’s most probably because some of the assets is returning 404 error. Please check your site after applying above settings, and also check for 404 errors. Let us know the URLs that are returning 404 error.