What custody actually adds
A custodial structure introduces obligations that have nothing to do with trading: the operator must stay solvent, stay operational, process withdrawals promptly, and keep your assets segregated from their own. Each of those is a separate way to lose money while the strategy itself is performing fine.
That does not make custodial platforms illegitimate. Regulated, well-capitalised custodians manage this competently every day. It means you are underwriting an additional risk and should price it.