I am following few SharePoint sites and the page - https://[[SPOnlineTenant]]/_layouts/15/sharepoint.aspx, is showing page name(.aspx) for few sites instead of the Site Name. Could you please help me to fix this issue.
What is the template of the sites which showing .aspx (Page Name)?
Are these Office 365 group sites or classic sites or communication sites?
Are you created them by using the "Create site" button on sharepoint.aspx page?
Is Overview.apsx the home page of the site?
Here is the similar issue post for your reference: