Hi @Flórida da Graça Botelho Araújo ,
You need to set your account as a site collection administrator,then you can Log in to your SharePoint site as a site collection administrator. Please refer to: 3 ways to make a user a Site Collection Administrator
It is possible to enable anonymous access to the entire web site using powershell.
PowerShell to Set anonymous access on specific SharePoint sites:
Add-PSSnapin -Name Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue
$web = Get-SPWeb https://sharepoint.crescent.com/sites/operations
#Enabled - lists and libraries; On - Entire web site ; Disabled - Self explanatory
$web.AnonymousState = [Microsoft.SharePoint.SPWeb+WebAnonymousState]::Enabled
$web.Update()
Referenc: https://www.sharepointdiary.com/2014/05/enable-anonymous-access-using-powershell.html
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