(1) It’s billions of years, and
(2) If you could capture enough sunlight to “lift” the star’s mass away to slow down its rate of burn it could be billions of more years, see
https://academic.oup.com/mnras/article-abstract/523/3/3251/7...
https://en.wikipedia.org/wiki/Star_lifting
(1) It’s billions of years, and
(2) If you could capture enough sunlight to “lift” the star’s mass away to slow down its rate of burn it could be billions of more years, see
https://academic.oup.com/mnras/article-abstract/523/3/3251/7...
https://en.wikipedia.org/wiki/Star_lifting