How to handle product launch limits on a new account?

Hello!

On day 19 we need to do a product launch on shopify.

We will be limited to selling only one product at the moment:
https://webinarprotest.myshopify.com/products/meta-ads-dalla-a-alla-z

With visual composer: gempages

I wanted to ask:

Do we have limitations in selling being a new account? Can we sell €20k between paypal payment and direct paypal without limitations?
We will probably upgrade to “Advanced” plan before launch.
What do we need to watch out for being a newly created account?
Do we have concurrent user limits? we anticipate a large influx of concurrent users and don’t want the site to go down.
We will also ask gempages support, but on your side are there limitations?

Thank you! We would like to start with this launch and in the future move our ecommerce activities to shopify.

Thanks

Simone