concurrent users and pagespeed

Hi guys

Running opencart v 3.0.2.0 on a VPS

I am wondering if there is a theoretical limit to concurrent users/pageviewers and what the best way to deal with the (happy)problem of a spike in traffic from say media attention.

New to the opencart platform & since Covid-19 I had to close my restaurants so I have set up an online shop. This has resulted in some media attention in the locality - one spike seemed to hit a wall around 300 concurent users with page load times running up.

At the time I had the site on a VPS with 4 cores CPU, 8GB ram. I have since doubled this to 8 cores and 16GB - we are starting a further marketing campaign with a few spots on national radio which will lead to a traffic spike (I hope)

My question is, will doubling virtual resources double theoretical capacity or is there a theoretical limit within the opencart software?
Generally we have 30 - 60 concurrent users and page speed of around 3.5s which I know is high and am working on using guidelines from google lightspeed, should I move to dedicated hosting to deal with any spikes or would a CDN be a better move like cloudfront or cloudflare - how much of the resources on my VPS would be used by php/MySQL vs delivering images & css which could utilise a CDN?

Appreciate that this is opensource software, and I have limited experience in the opencart universe so if there is an obvious answer to this in documentation please let me know, I couldn't find much. The conversation on other posts in the forum seems focused on max number of products not max viewers as well so haven't found much.

Thanks in advance!

8 cpu and 16gig ram should be more than enough if your server setup is fully optimized.
Make sure Apache is optimized, MySQL is optimized and PHP is optimized
You could optimize oc database wich wil reduce lading time a lot.

If you need help on this Just drope a pm of email.

Hi there

Thanks for your reply. Apologies I did not get notified when you posted it so I missed it. Site is optimised now.

Thanks for your advice