Hi there,
I'll keep it short. I have 14+ years of experience in Web development and after reading your requirements I'm 101% confident I can help you with your task. Just to prove my coding skills, you can test me in any way you want, be it by solving a short but complicated task or answering questions. Moreover, my english is great so you can be sure that there will be no language barriers.
Regarding your project, to import this csv using any browser based, it cannot be done as it exceeds the 60 seconds timeout for PHP and the csv is too large to be imported into PHP from browser. The best solution in this case is to create a script that will run in the background of the server. It will read the csv file line by line, it will use WooCommerce functions for adding products and WordPress core functions. We can make a page in the Admin that will activate or deactivate the script, you'll have error logs, success logs etc. Using this method, while the script imports the data into WooCommerce, the website will run flawlessly, without any downtime/problems.
When you're available, ping me with more details so that we can take it further and get this done ASAP.
Looking forward to helping your reach your goals and build a great business relationship.
Regards,
Kalin Ross