A little about myself, I know HTML, CSS, SASS, Tailwind, JavaScript, React, PHP and a bit of wordpress. Basically in wordpress i use the Gutenberg editor i think to build but mostly i just use ACF and custom code in the back using PHP using CPTs. That's mostly I know. I havent used most of the plugins and when i do use some then i kind of struggle getting it to work as i wanted i guess.
I know there is like popular page builders like Divi, Elementor etc to build a website but i have a client which basically has a requirements like how they want the website to look like. They have like tons of products and depending upon categories and stuff, they would want it designed differently. Also later on as I progress with the website they want to add features like ecommerce which i would have to use WooCommerce, Also they have like 2 stores and want to track inventory with 2 different SKU number for same products based on the items. I am not sure like how to proceed, Should I use some themes or page builders or custom with CPT and acf?
Anything i would need to learn extra to build a site like this?

Custom will always be ideal, but if dev time and cost is a factor, there’s no need to reinvent the wheel for 95% of sites – off the shelf plugins for standard everyday things like ecommerce are more than sufficient.