About the sore point: speeding up and optimizing WordPress.
Key points that often need to be clarified
WordPress is a content management system with dynamic content and a database.
This isn't a website builder. And the word "WordPress" doesn't affect your search engine rankings or website speed. With the right development approach, no one ever uses plugins to speed up a WordPress site!
Why write unnecessary code upfront for a template design, only to have to compress it later with three or four plugins? Code is a set of characters; at a minimum, it should be written correctly and tailored to the design; at a maximum, it should be compressed into a single line.
A problem popular with many 
If your website has speed issues, it's likely created using a Themeforest template by an inexperienced freelancer or by you following YouTube tutorials.
Is the design unique? - Yes!
Many website owners don't even realize they're using a nulled template from Themeforest as the basis for their site. Experience has shown that contractors often rename theme names and remove links to the actual developers, claiming their work is their own.
Themeforest and other similar marketplaces aren't evil. I have nothing against them! You can always find brilliant design solutions and high-quality templates there to launch a website in a couple of clicks or test out ideas.
But the problem with such templates is that they typically rely on 15 or more generic demo designs for all occasions. This means that the template's CSS/JS libraries contain 70% of the code that website owners never actually use.
In addition, each template comes with 20+ built-in plugins, ranging from sliders and contact forms to website builders and Woo-powered online stores.
Even the product filter widget requires a separate plugin. In fact, I often see a trend among WordPress owners: they always install a plugin for everything. Menu icons are a plugin. Changing the icon color is a second plugin. Translating the plugin into Russian is a third plugin.
That's how clutter and unnecessary libraries accumulate in the code. Sometimes it gets ridiculous: three identical JQuery libraries in the header of different modules.
A trivial example: Contact Form 7 isn't used for forms on most pages, yet it loads its libraries globally everywhere, thereby slowing down the site's page load times.
What should be done to solve the problem?
It's all simple and indifferent. The stingy pay twice. The customer of 500-ruble exchanges pays sixteen times. There are exceptions, of course, but that's generally the case.
For long-term success, a website needs to be developed from scratch, from design to WordPress. A semantic core needs to be compiled and content needs to be written. This will ensure both a green zone in PageSpeed Insights and search traffic.
Or, if your budget is limited, carefully select a high-quality template that can be used to launch a successful project, optimize the template manually, and minimize the number of plugins used.