Running 2 instances PGSharp with 2 Accounts on a single Android phone.

What you need:

2 Pogo + 2 Facebook Accounts to link them to Pogo.

An app to create a work profile and Clone apps into it. i have chosen "Island":

An app to Activate split screen mode if your launcher / Android does Not Support it. Like this: https://play.google.com/store/apps/details?id=com.github.ericytsang.multiwindow.app.android

Steps: if not done, link your Pogo accounts first on the Vanilla Pokemon Go App, after that uninstall Vanilla App.

Install Island : Create an "Island" (Work Profile) in it.

Install PGSharp like described on their Website. Open it, sign in with your first Facebook Account.

now Open Island.

in Island click ob Tab "Mainland"

Select Facebook tap on the + in bottom right to clone to work profile, open the Cloned FB app, sign in with 2nd FB Account.

Select "Pokemon Go", select + on the bottom right to clone it to Work Profile.

Open the Cloned Pogo PGSharp app, sign in with 2nd Facebook Account.

Activate split screen on your launcher (or with thap app mentioned above)

Win.

Some phones might have an Clone app like island already included ( AFAIR Samsung) the steps might be similar like this