Hi @maatouch.freelance and welcome to the forum,
The banner will stay for as long as you’re on the free plan.
Of course there is no banner on the new anvil open source runtime so that is potentially an option. But then, you would need to host the app yourself.
I think anvil’s model in this regard will be, while you’re testing the waters the free plan will allow you to know if anvil is for you, and then the paid plan will be necessary if you want anvil to host your web apps, without the banner, and with the other benefits that come with the paid plans.