In case you want to update the My Account headers, for example, the header tab text My payments & History or My vouchers, you can update this directly in the My Account templates under Manage → Templates → My Account Templates.
In the relevant My Account code remove the context inside the <t> tags.
For example from this:
<t>context="checkout.platform" My payments & history</t>
You would update it to this:
<t>My payments & history</t>
The same logic can be applied to any strings using the checkout.platform context found in System and My Account templates.
Please reach out to Piano support in case you'd like to have the strings translated without removing the checkout.platform (or other) context. They can update the translations on our backend.