In my tests of a database recreate (My experience with Database Rebuild / Recreate) I found it took about 4.25 days to recreate an 853 MB sqlite file (built on ~1TB of source content). If what I suspect is correct, the time it takes for a rebuild will get progressively longer the larger the resulting database should be.
I believe most of the issues performance issue with a rebuild is in the local database reads checking if blocks already exist or still need to be added. If that’s correct, the only way I can think of to speed it up would be to have the database stored on an SSD or ram drive - neither of which is something you can do once the recreate is started.
Since an interrupted rebuild can’t be continued (you’d have to start over) I’d suggest just waiting it out.
If you want to make sure things are stalled, you could take a look at the “lastPgEvent” line of the “System info” page or use a filter like “Profiling” on the Live tab of the the main menu “About” -> “Show log” page.
But that won’t make it go any faster. 