This is the form for reporting malware on Play, and it includes a free-form text input for describing the issue:

https://developers.google.com/android/play-protect/pha-repor...

(It is a bit odd that there's no DoS category on the report form, despite it being listed as a category on their taxonomy page at https://developers.google.com/android/play-protect/phacatego..., but I expect that you can just enter that in the "other" free text field.)