For those who need a working solution now, here is my Tasker profile.
https://pastebin.com/raw/6HThWHFN
What’s needed:
- Tasker with provided profile imported (https://tasker.joaoapps.com/download.html)
- Magsik for root access (requires unlocked phone) (How to root the Fairphone 3?)
What it does:
- enables red led when either Conversations, K9, Signal, Threema, Riot or QKSMS show a notification
- disables the led if these notifications go away
Feel free to tune it to your own needs. See it in action in this comment: LED notifications do not work