Slate Plus has non working Adguard Home since 4.2.0

[slesar]

How-To: Update AdGuard Home [Testing!]

Hi there some people wonder how to update the AdGuard Home version on devices like the Flint or Flint2. For your convenience, I created a script to automate this process. Make sure to read and understand this post before you go on! Permanent feature I added the option to make all changes permanent. The script therefore only needs to be executed once, the effects are then permanent. Even across firmware updates. On the downside, it might create trouble when you flash a way older firmware…

Try this guide from @admon.
Looks like your config.yaml has changed command when upgrade adguard home. Inside file must be your list filters.