Pinpoint sendMessages Template support for nested substitutions

I am trying to use Pinpoint sendMessages method to send emails leveraging the Pinpoint templates as well. The feature is great but I think is lacking a needed capability to parse nested attributes. It looks like all you can pass as attributes to the template is a map of keyvalue pairs of strings or array of strings. I need the support for a bit more hierarchy in my data, similar with what SES supports in this below link: https://docs.aws.amazon.com/ses/latest/dg/send-personalized-email-advanced.html#send-personalized-email-advanced-nested

Anyone knows if I am missing something?

Notes: I found this workaround how to achieve the same in Pinpoint but seems to much manipulation of data is needed just for the sake of the template. Looking for something more simple and honestly I think it should be supported as SES has exactly what I need https://aws.amazon.com/blogs/messaging-and-targeting/advanced-amazon-pinpoint-templates-using-message-template-helpers/