If you're selling tickets for lots of events on your own website, your recommended set up is to:
Add multi-checkout to your box office
Add your custom domain to your box office
Embed a widget, plus a cart widget on your box office
If you're also tracking pixels to help with your marketing, the additional cart widget may slightly affect your analytics, but this shouldn't be significant. The cart widget will be tracked as well as your regular widget.
What pixels will I see in my analytics when I have a widget and a cart widget?
The cart widget iframe fires a PageView/gtag config when it loads, and the normal widget does too.
These are in separate iframes with separate page contexts, so your analytics tools will see them as separate page loads.
You should expect to see separate page loads from the cart widget in your analytics dashboards.