custom fields translation (Not by ACF)

Hi there,

Is there a way to translate texts in custom fields (per post) that come with a theme?

For example, my theme has a custom field for “subtitle”. While using this plugin, I input {:en}subtitle{:}{:ja}サブタイトル{:} in the field but that didn’t get translated.

I am a new user looking for an alternative to qtranslate-x, where it was easy to translate custom fields. I wonder if this plugin could do the same so I could decide to switch to this plugin completely.

Thanks in advance for your help.