Annotation:
For Joomla 4 you also need the template for J4.
Your template: VALENCIA is already available for J4. You have to buy this again. For each template that has already been purchased in J3, there is a discount code for the same user...
look here:
https://www.joomla51.com/blog/item/joomla-4-template-update-timeline


Info: https://www.joomla51.com/tutorials/joomla-basics/updating-your-joomla-template

Many thanks for the coupon.
My trouble is Valencia-J4 can run on J3.10.11?

There are bound to be problems if you want to run the J4 template in J3!
(first make a backup of the site !!)
I installed the new J4 template on several sites and then updated it directly to Joomla 4... (you should test this locally on your computer or on a test site) You should not run the J3 site temporarily with the J4 template!