Hmmmm, so it appears to be neither a reboot, or a large scale relaunch. Just read this line in the Newsarama/Gamesradar piece:
"Then in March, the regular DC title lineup resumes with the numbering of existing series intact, "continuing existing storylines from 2020 and introducing new arcs for the year."

I'd imagine some series may get a new #1. Justice League seems to be an obvious candidate. The last volume basically just existed to be a Death Metal prologue. Whatever Taylor's Suicide Squad follow-up is?