Despite all the risks, I wouldn't say having your seed phrase sharded to three companies is higher risk than simply having Ledger "look after it" for you.
I wasn't asking about the seed and storing the seed this time. I meant who stores the KYC data (the IDs and selfies). Your link confirms that Onfido is their partner for that which answers my question.
They do claim the seed can only be decrypted with the same Ledger that created it, but I imagine with any Ledger there would be a simple workaround for this, such as spoofing the device's log number in order for the encrypted shard to think it's the same one.
I have heard the opposite. You don't need the original device you used for Ledger Recover and seed sharding. Since the shards are connected to your identity (the ID and selfie you provide), the hardware wallet device is of secondary importance here.