Could you please check how it works with some default WordPress themes like TwentyTwenty or WooCommerce Storefront to understand is it our theme issue or not?
In this case, you need to create a staging development copy of your website. There, you will be able to do such kind of experiments without any harm to your production website.
Usually, such issues are not caused by the theme itself. It might a general problem for your website. That is why you need to test it with the default WordPress theme.
I have the same issue since the update of 10 november I have several pages that are noindex that were indexed before and had high google rankings. Did you manage to resolve the issue? And how?