Change theme .php file and keep changes after update

Hello,

The theme I use for my website has a footer text that credits the theme creator(s) (WordPress Theme by example123). I know support is important, but I’d rather pay them than having such a text at the footer of my website.

Anyway, the theme includes a footer.php in which this text is declared. This can easily be removed or edited by changing the text in this file. Which works fine, however, after every theme update I have to do this again manually.

Is there any way to prevent the text from changing back after every theme update? Maybe with a child theme? I did some research but I am not a php expert and I couldn’t really find a solution for this problem.