A desktop publishing application from Microsoft that focuses on page layout and graphic design.
Canva can be a great choice.
And as you have already heard, the Microsoft 365 apps are available for free online. You don't get the more sophisticated features of these apps, but most people will never miss them. The only other limitation with free Microsoft 365 is that your files are stored in your OneDrive, which doesn't matter for most people.
If that's not enough - if you're like Oliver Twist and you want more - there's also Google Docs, Sheets and the other Google Workspace apps, all for the outrageous price of ... free.
Still not enough choice? Check out Libre Office, WPS Office and the other choices you can find with a web search for: Microsoft office alternatives. Any of these create files that can be opened with Microsoft 365, leaving open the possibility of a future change of heart.
But you won't find anything that's just like Publisher. The market for apps that create paper-based content has dwindled. Other developers got out of that market long ago. Microsoft was the last holdout with Publisher, and it doesn't make financial sense to keep it going. Content is digital now. Microsoft gave customers more than two-and-a-half years notice before pulling the plug on Publisher, but the day is almost here.