For your information, I asked my BLS privkeys to AllNodes and I had to wait more than one week and multiple messages to have them.
But, finally, they send them to me 
and the migration to NodeHub.io was very simple : just the TXID and the BLS key for each node.
Edit : july 30 2024 : since mid-may, so 2.5 months ago, no problem with NodeHub.io and the price is still $0.13 per day, or $3.90 a month (30 days), I created a new Firo masternode a few days ago (my previous masternode was’nt creation but migration) and the initial creation fee was only $ 0.06 (it was $5.00 at AllNodes.com and I think now it is $10.00) !!!