I use several custom fields in virtuemart that are editor type.
Then when I assign this custom field to a product I can use JCE editor tu put what I want.
But since the v2.9.12 I do not have JCE anymore, but just the raw html instead.
I must say that JCE appears normally for the edition of the product description.
If I reinstall JCE 2.9.11 all is fine, editor appear normally.
I'm with Joomla 3.10.1 and just in case Virtuemart 3.8.6