Elemenets 2020 does not support ACR 12.4. I have no idea whether it will do so in the future. You still have the option to use the free Adobe DNG converter which allows you to batch convert your raw files to the DNG format and use them in Elements 2020.
Would you happen to know when the next version of Elements is supposed to be released? I'd like to have a version where my camera raw files are compatible. I'd imagine the next version will be the one.
I have no knowledge of any release date. The past four versions were released in October. I suppose that the global pandemic may cause some delay. Draw your own conclusion. In the meantime, you can get a 30 day trial of Elements 2020.