You can try with this api:
Get https://dev.azure.com/{org name}/{project name}/_apis/wiki/wikis/{wikiIdentifier}/pages?path=/&recursionLevel=OneLevel&api-version=5.1
Note: If you want to list all of wiki pages, need to specified the value of recursionLevel
in the url. This is the key word which specify the Recursion level for subpages retrieval.
For more details about this recursionLevel:
You can also refer to this doc: Get page as JSON with recursion level for more sample.
In addition, for programatically list wiki pages with rest API, here has an sample which execute with powershell can for you refer:
$uri = "https://dev.azure.com/{org name}/{project name}/_apis/wiki/wikis/{wikiIdentifier}/pages?path=/&recursionLevel=OneLevel&api-version=5.1"
$connectionToken="{Your PAT token}"
$base64AuthInfo = [System.Convert]::ToBase64String([System.Text.Encoding]::ASCII.GetBytes(":$($connectionToken)"))
$projects = Invoke-RestMethod -Uri $uri -Headers @{Authorization=("Basic {0}" -f $base64AuthInfo)} -Method GET
Write-Host "Pipeline = $($projects| ConvertTo-Json -Depth 100)"