A very big majority means government backbenchers have almost no power to influence policy and ministers can act as unchecked dictators. That's a big issue. It's not just the opposition who hold ministers to account.
Literally nobody warned that when Boris Johnson got his huge majority. BoJo was forced out... Truss was forced out. BoJo's Govt payroll was said to be quite large to keep his lot happy. The 2019 intake of RedWall Tories seemed to have a lot of influence. Quite a few accountability mechanisms in view.