Does the work made by vaccum in the current pass is lost when interrupted?

I have a large table (billions of records) which has not been vacuum and bloated.
Vacuum scale factor was left at the default.

I ran a vacuum on a DEV system and it makes several passes (scanning heap/vacuuming indexes/vacumming heap) which take more than an hour each.
On a PROD system, I may have to kill the job midway.
Should I reduce the autovacuum_work_mem of my session? Currently 1GB
Does the work made in the current pass is lost when interrupted?
Correct me if I am not right, but vacuumed indexes and heap made by the current pass will go to disk, but the heap should be rescan on the next vacuum.
I guess that the visibility map is updated only at the end of each pass.

My best regards

Thank you

Jean-Marc Lessard
Administrateur de base de données / Database Administrator

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