Hi, I'm a total newbie to wordpress and built a rather large wordpress woocommerce and membership website. I built it without knowing much about how images and plugins affect the speed. I have tried reducing plugins and images but still need many of them. A lot of it will be user submitted images as well so keeping images low is almost impossible. After trying to optimize it myself, it is still at a score around a C rating on gmetrix. I tried fixing the images with imagify and it is still getting low grades. I feel completely stuck as it is just me working on this. I would like to get it to a working speed level and am willing to invest in it. I researched many optimization services but am unsure if they are scams or not. Some reddit posts have said sites like upwork or fiverr are mainly scams and don't recommend them. Any trustworthy ones out there?

Well. I do SEO and i have an agency also, we are pretty good. Lets connect on DM
Did you add caching? Who are you hosted with?
I have some free plugins to handle some large-site performance issues. https://www.plumislandmedia.net/wordpress/performance/optimizing-wordpress-database-servers/
I also do reasonably priced performance consulting. If I can help you please contact be via the About page on that web site.
Check out plugins like airlift. You can also try service providers like wptasks.com or dreamhost pro services.
Bro now you want to use a good hosting thats it and what plugin are you using for clearing caches
Run that site through Cloudfare CDN! It’s free and offers tons of free optimizations and caching.. took my site from a 50 lighthouse score to 80+! Easy setup too!
Let me send you a guide .
> keeping images low
Use ModernImageFormat (https://wordpress.org/plugins/webp-uploads/) to convert new upload images to aif, and ForceRegenerateThumbnails (https://wordpress.org/plugins/force-regenerate-thumbnails) to convert already uploaded images.
WP site with Woo-commerce and membership need at least 2GB RAM (preferably 4GB) hosting. Do not use any EIG hosting.
At server side use OPCache, redis, memcached, varnish. If you need some WP cache plugin I recommend WPSuperCache+Debloat. Use of CDN for image caching (https://bunny.net/, https://www.quic.cloud/)
Serve fonts local or use only web safe fonts.
I could bet on bad hosting as source of problem.