Hi.,
Most of it depends on page content which compromises images. If images are properly optimized and you’re using a cache plugin and a good fast host, the speed issue shouldn’t happen on any theme.
You can try this plugin to increase theme speed –
Documentation: https://assetcleanup.com/docs/
Please refer to the Video: https://www.youtube.com/watch?v=_in5ZNZ3C-M
Please Optimizing Images with WP Smush
Plugin : https://wordpress.org/plugins/wp-smushit/
More Details : https://www.wpbeginner.com/plugins/optimizing-images-with-wp-smush-pro-cons-and-alternatives/
Thank you, we look forward to helping you!