Demos are bloated versions showing everything off and not a reflection of actual optimised use (this will be the same for any theme)
The author @Wolf-Themes is a power elite so going to produce great items.
Stock themes are not meant to be off the shelf finished solutions and there’s an expectation that you would invest in decent hosting and optimise the website for use.
You can ask for a refund especially if you have not yet downloaded or installed it but a) this definitely would not fail under typical reasons for it being approved and b) you are likely to find the same problem with many other themes too.
Just to reiterate - it’s more than just installing it, you need to be using proper hosting and go through the process to minify code, optimise assets, and so on. Good luck
In addition to @charlie4282 reply, here is some complementary information to help you speed up your loading time.
First, be sure that your theme and all plugins are up-to-date and that your server fulfills the minimum server requirements.
Issues you may encounter, such as demo content fails when importing, slow loading speed, and similar issues, are generally related to very low PHP configuration limit settings. Please see our demo as a reference. It offers the exact same content but it loads pretty fast.
For more help, please post a ticket in the WolfThemes support forum with your website URL and login info. We will get back to you as soon as possible. https://wolfthemes.ticksy.com/