You can tackle the images first which is a big issue for your website’s performance.
It’s suggested to use next-gen image formats like WebP or AVIF. Try changing the format of your images manually, or, you can also use a plugin to do so. I believe Smush can do this (not sure if you’ll need the pro version): https://wpmudev.com/docs/wpmu-dev-plugins/smush/#WebP-Conversion
Moreover, you can also try using a CDN to further improve performance.