Firms that do standard financial audits for companies with cryptocurrency holdings?

Generally speaking, the larger accounting firms will not do standard financial audits for firms with crypto holdings. I suspect reputational risk is too high for their risk appetite. I know there are companies that do things like reserve audits, but I would like to know if there are any firms who will accept an audit engagement for a standard financial audit. There must be a boutique-type firm in this space that specializes in such things; does anyone have a lead or know the companies that do this?

Thanks.