Which one is more beneficial for faster ranking results, onpage SEO or offpage SEO?

In my opinion, On-page SEO and Off-page SEO both are important for ranking in any search engine. But First of all, you have to focus on your On-page SEO and then you need to go for Off-page SEO. Just remember when you do your off-page SEO make it authentic and genuine.

On page SEO will definitely rank your website better. Most of the ranking comes from the work you put in with your SEO and keyword research within the website itself.

The off-page SEO is only there to back up the on page SEO.

Think about it if you had next to nothing on your own page in terms of content, yet you have an amazing amount of off page SEO. All search engines would basically be trying to rank a 'blank' website.

Both have their own importance, without OnPage Activity one cannot perform Off Page Activities

Both are important!!