Restore deleted registry entries without any backup

So, the whole whole problem originated when I noticed the Avira Antivir was constantly taking up more than 30 % CPU usage and I wanted to get rid of it. I deinstalled all avira-related programs but after rebooting some avira processes were still running.

A quick google search suggested deleting all avira-related registry entries and this is where the pain begins. Foolish me didn't thing I was going to need a registry backup and now here I am without one and probably missing registry entries.

After I finished deleting everything that Strg + F could come up with related to Avira, my laptop doesn't recognise the speakers or the audio output. So this is what I have tried until now:

• Checked device manager: All devices are working without issues
• Reinstalled the audio driver provided by lenovo (Driver says: Please connect a speaker to the system)
• Tried to restore the system with earlier restore point
  • Restoring failed, so I undid it
    After doing so all restoration points prior to deleting the keys were deleted -> Sytem Restore is no longer an option
• Google search said scf \scannow is an option
  • I let it run, damaged files could partially not be repaired
  • Did not fix my issue
  • Log-Entries:

2019-11-15 02:58:20, Info CSI 00005c73 [SR] Cannot repair member file [l:9]'MSDTC.LOG' of Microsoft-Windows-COM-DTC-Runtime, version 10.0.17763.1, arch amd64, nonSxS, pkt {l:8 b:31bf3856ad364e35} in the store, hash mismatch

2019-11-15 02:58:20, Info CSI 00005c75 [SR] Cannot repair member file [l:23]'MSFT_MpPreference.cdxml' of Windows-Defender-Management-Powershell, version 10.0.17763.831, arch amd64, nonSxS, pkt {l:8 b:31bf3856ad364e35} in the store, hash mismatch

2019-11-15 02:58:20, Info CSI 00005c78 [SR] Cannot repair member file [l:9]'MSDTC.LOG' of Microsoft-Windows-COM-DTC-Runtime, version 10.0.17763.1, arch amd64, nonSxS, pkt {l:8 b:31bf3856ad364e35} in the store, hash mismatch

2019-11-15 02:58:20, Info CSI 00005c79 [SR] This component was referenced by [l:145]'Microsoft-Windows-Client-Features-Package01~31bf3856ad364e35~amd64~~10.0.17763.1.85D825745BF46BA77A67DC2EC21821B5C44555B73AD5B87E1405BABA326A43FB'

2019-11-15 02:58:20, Info CSI 00005c7d [SR] Cannot repair member file [l:23]'MSFT_MpPreference.cdxml' of Windows-Defender-Management-Powershell, version 10.0.17763.831, arch amd64, nonSxS, pkt {l:8 b:31bf3856ad364e35} in the store, hash mismatch

2019-11-15 02:58:20, Info CSI 00005c7e [SR] This component was referenced by [l:81]'Package_2978_for_KB4523205~31bf3856ad364e35~amd64~~10.0.1.10.4523205-4344_neutral'

• Next try was DISM Restore Health (and CheckHealth)
  • Check Health said component storage can be repaired and
    Version: 10.0.17763.771 Abbildversion: 10.0.17763.864 (are the different versions a problem, I have the latest windows version installed and downloaded the iso from windows (MediaCreationTool)
  • Code Used: Dism /Online /Cleanup-Image /RestoreHealth
  • Result: Error 0x800f081f (Source not found)
  • Downloaded .iso from microsoft website, decompressed it and used both .esd and .wim as source. Code Used: Dism /Online /Cleanup-Image /RestoreHealth /Source:C:\Users\thorb\isodatei\sources\install.esd:1 /LimitAccess
  • Result is the same as without the source but with dism /Get-WimInfo /WimFile:C:\Users\thorb\isodatei\sources\install.esd I can access that exact file

    Index: "1" Name: "Windows 10 Home"
    Beschreibung: "Windows 10 Home"
    Größe: 14.645.220.131 Bytes

So, is there any possibility to get the entries back without reinstalling windows or is that my last chance? Sorry for the very long post and thanks in advance for any help!