We are going to migrate our current HTML site to WordPress site and also HTTP to https migration for the same website, The entire URL structure changed now.

Which one I have to use from the below options, without losing SEO benefits.

1. .htaccess domain level 301 redirection
2. using any plugins to redirect every HTML pages to WordPress pages (It is a large process).
3. .htaccess domain level 301 redirection with plugin redirect for important 4 0r 5 HTML pages to WordPress pages

If we are migrating HTTP to https I can use .htaccess 301 redirection, but in our case URLs are also changed due to HTML to WordPress migration.