As a part of the sale of HGST to WD, Toshiba got assets to produce 3.5” hard drives from HGST. I’d consider them the true heirs of HGST, and their good reliability as shown in Backblaze’s studies bear that out.
Unless WD changed their mind again, HGST HDD is still available as of 2021 because customer has been demanding the exact same HDD with exact same model number from the exact same plant. Basically they want to know it is the same old HGST and not WD. And some ( if not most ) of them are large, enterprise customers. So they brought it back in ~2019 (without an announcement).