Restoring course is very slow

Dear all,

I am using Moodle 4.2.1+. I try to restore a backup course of size 1.8G. The restoring process behaved strangely. It got stuck  at 0.1%, showing the estimation time 7 days as in the below snapshot. After a while, the status bar just moved up. But the speed was still very slow. I just wonder why the restoring process takes a lot of time. Can I fasten it up ?

Many thanks