On this website I read:

Version 3.0.1 Compatibility Joomla 4 Joomla 3 PHP 8 Framework Helix3

If I install it I read :

Shaper Onepage is the sleek, fully responsive and perfect one page parallax template for corporate, agency, nonprofit, freelancer or general business with attitude. It gots a fullscreen slider with custom captions, an Awesome portfolio and contact form, a blog and tons of styling options. Its built with twitter bootstrap and very well coded so it is very easy to edit and modify things. Also font Awesome icons and many more super-awesome features to keep you busy & satisfied. Key Features Unlimited module positions with the power of unique layout builder Built with Helix-3

Powered by Bootstrap and compatible with Joomla 2.5 and 3.0

Three (3) presets with presets manager Uses latest web technologies like html5 and css3 Tons of shortcodes in built Built with LESS CSS Megamenu, RTL Support, CSS and JS compression and many more...

It's compatible or not whith Joomla 4 and PHP 8?

Best regards