Add Signal app to Parallel Apps Menu
Here, submit a suggestion via https://forums.oneplus.com/feedback/
Isn't the availability of parallel apps with the app developer themselves? Not sure if signal has parallel app availability.
Also, there is an app called island that essentially allows you to duplicate an app. Not sure how it works exactly but it's worth looking into
Can use 3rd party app instead
Weekly Update 376 – A meaningful week
by Olive W., 2021-02-26