You can use the Joomla Redirect component:
System -> Manage -> Redirects
or in the advanced Shield settings
Custom Rules -> At the beginning of the file
insert your .htaccess redirect rules.
When setting up HTProtect for the first time, any existing redirects from the previous .htaccess should be automatically offered for one-click import.
For creating the rules, you can use tools like this:
https://static.app/redirect-generator
RewriteEngine On
is not needed at the beginning – it’s already on at that point.