I performed a test few months ago,
I got some sets of backlinks 10k links each set
I used many famous names indexer services.
I believe that no one of all these indexer services are working "or doing anything" except Indexification
However, the links are not indexed too with Indexefication (or we can say it is just a small percentage that getting indexed)
But I see some work happened for the links set.
So currently I'm just using Indexification, but I made a difference test this time.
I used human-quality articles in submission, and submitted couple of backlinks in some high DA sites.
then send to indexification (instant & 7 days)
in few days more than 50% of links are indexed.
I'm still checking the best way to get links valuable, as I also added some social signals and some visits to these backlinks.
I like to share this test case with you as it may help you