This generates as sitemap.xml for TYPO3 only with Typsoscript. This example is with realurl and news. (tx_news) . Tested in TYPO3 8 LTS. Use "Sitemap: https://www.example.com/?type=200" in robots.txt to point to it.

robots.txt

User-Agent: *
Disallow:
Sitemap: https://www.example.ch/?type=200

typoscript_sitemap_with_tx_news.ts

### Thanks & Credit for this to http://www.adick.at/2010/06/01/typoscript-xml-sitemap/
# write paht to sitemap in robots.txt as "Sitemap: https://www.example.com/?type=200"

xmlSitemap = PAGE
xmlSitemap {
  typeNum = 200
  config {
    no_cache = 1
    disableAllHeaderCode = 1
    additionalHeaders.10.header = Content-Type: text/xml; charset=utf-8
    simulateStaticDocuments = 0
    tx_realurl_enable = 1
  }
  10 = COA
  10 {
 
    wrap (             
<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">|</urlset>              
    )
 
    10 = HMENU
    10 {
      special = directory
 
      #Ausgangspunkt / Root Seite
      special.value = 1
 
      #1 = Standard
      #2 = Extended
      #3 = Extern URL
      #4 = Shortcut
      #5 = Not in Menu
      #6 = Backend User Bereich
      #7 = Mounted Page
      #199 = br
      #254 = Sysfolder
      #255 = Recycler
 
      excludeDoktypes = 2,3,5,6,7,199,254,255
 
      1 = TMENU
      1 {
        expAll = 1
        NO {
          doNotLinkIt = 1
 
          stdWrap {
 
            cObject = COA
            cObject {              
 
      wrap = <url>|</url>
 
        10 = TEXT
            10 {
              typolink {
                parameter.field = uid
                returnLast = url
                forceAbsoluteUrl = 1
              }
              wrap = <loc>|</loc>
            }
 
            20 = TEXT
            20 {
              field = SYS_LASTCHANGED
              strftime = %Y-%m-%dT%H:%M:%SZ
              wrap = <lastmod>|</lastmod>
            }
 
            30 = TEXT
            30.value = <priority>1.0</priority>   
 
            if.isFalse.field = shortcut              
 
      }
 
          }
 
        }
      }
      2 < .1
      2.NO.stdWrap.cObject.30.value = <priority>0.9</priority>
      3 < .1
      3.NO.stdWrap.cObject.30.value = <priority>0.8</priority>
      4 < .1
      4.NO.stdWrap.cObject.30.value = <priority>0.7</priority>
      5 < .1
      5.NO.stdWrap.cObject.30.value = <priority>0.6</priority>
      6 < .1
      6.NO.stdWrap.cObject.30.value = <priority>0.5</priority>
      7 < .6
      8 < .6
      9 < .6
      10 < .6
    }  
 
    # and news records...
  
    20 = CONTENT
    20 {
            table = tx_news_domain_model_news
            select {
                //orderBy = title ASC
                languageField = sys_language_uid
                pidInList = 110
            }
            renderObj = COA
            renderObj {
                stdWrap.wrap = <url>|</url>
                5 = TEXT
                5 {
                    typolink.parameter = 112
                    typolink.additionalParams = &tx_news_pi1[news]={field:uid}
                    typolink.additionalParams.insertData = 1
                    typolink.returnLast = url
                    typolink.forceAbsoluteUrl = 1
                    wrap = <loc>|</loc>
                }
                10 = TEXT
                10 {
                    field = tstamp
                    strftime = %Y-%m-%dT%H:%M:%SZ
                    wrap = <lastmod>|</lastmod>
                }
                20 = TEXT
                20.value = <priority>0.7</priority><changefreq>weekly</changefreq>
            }
        } 
  }