Gutenberg is not allowing Polylang tanslate template parts

I hope this message finds you well.

The issue is: Polylang is not showing the languages for the template parts.

Accoring to Polylang team’s, it appears that the missing language Metabox is caused by the plugin Gutenberg version >= 17.1.0. The issue doesn’t occur any longer with the previous version (17.0.3) of that plugin.

I have opened an issue to Polylang developers team to be able to analyze the changes performed by that plugin and find a solution.
In the meanwhile, I’d like to downgrade Gutenberg, but my site is wordpress.com and Gutenberg is a host-managed plugin. How can I do that?

Regards,