RewriteCond %{THE_REQUEST} \s/+blog?start=19[?\s/] [NC]
RewriteRule ^ https://drugoysite.ru/blog/ [L,R=301]
Redirect 301 /blog/ https://drugoysite.ru/blog/
RewriteCond %{REQUEST_URI} ^/blog/$
RewriteRule ^.*$ https://drugoysite.ru/blog/? [R=301,L]
RewriteCond %{THE_REQUEST} " /blog\?start=19 "
RewriteRule ^ https://drugoysite.ru/blog/? [L,R=301]