Process Oreos to fine crumbs. Mix with melted butter and salt until combined. Press firmly into a 9-inch pie dish. Refrigerate for 15 minutes.
Melt dark chocolate in 30-second microwave intervals, stirring between each, until smooth. Cool until barely warm.
Beat softened cream cheese on medium for 2 to 3 minutes until completely smooth.
Add condensed milk and beat on low until combined. Add cooled chocolate, cocoa powder, vanilla, and salt. Beat until deep, uniform, and fully smooth.
In a separate cold bowl, whip cold heavy cream with powdered sugar to firm peaks. Fold gently into the chocolate mixture in three additions.
Pour into the chilled crust and smooth the top. Cover with plastic wrap and freeze for a minimum of 5 hours or overnight.
Whip cold heavy cream with powdered sugar and vanilla to medium-soft peaks. Spread or pipe over the frozen pie.
Top with chocolate shavings and mini chips. Dust with cocoa powder. Finish with a pinch of flaky sea salt. Slice with a warmed knife wiped dry between each cut. Serve immediately.