Impossible de migrer un autre design vers domaine

After asking the interface how to increase the size of a logo or change the site template, I’m told it’s impossible.
However, as templates are very limited, I create a new site design on the Canva platform, whose design can easily be redistributed…. but not on site123.

As the domain name was purchased via site 123, I’m told it’s my domain but I have no rights to it.
So, if you have flyers or business cards…. with this domain, throw everything in the trash.
I paid almost 200 euros chewz them not to have the restrictions of the free version, but it’s going to cost me a lot more.