for the S-Pen, I have been using AOSP rom 8.1
if you love AOSP and have a good reason to flash it, then it is possible to gain back some of the spen features in AOSP, not as smooth as in Sammy's Roms but ok, I posted what i did here
, there is even a video showing what I did. it involves root, and xposed, (now ed exposed)
as for the spen bluetooth capability, the Spen is still active and recharges by itself. if you download nRF connect
apps from playstore, once you click the button you can see the pen as a bluetooth device SPEN (0D27) ZK, through these apps you can even subscribe to the service and get notifications when the button is pressed, so techinically speaking if someone has app development knowledge this can be done easily. to my limited knowledge I documented what I have discovered here
I have suggested to nRF connect App devs if they can have a tasker plugin so we upon a spen button click we can use tasker to make different actions, they reacted positively, the dev mentioned that they might work on it but might take some time since they are short resourced. but been some time since.
I did a funny workaround once, they keep the log in data/data/no.nordicsemi.android.log/databases, so when that file changes you can read the line change and read the button event, and trigger a tasker action.
its doable, just needs a proper dev that works on it. an AOSP spen remote, or even a custom BLE notification tasker plugin if he wants to make it universal and target alot of devices such as smartwatches..
last note: if the spen works funny in landscape, there is a post in the same thread showing how to fix it.
I will flash this rom today.. Thank you for the awesome work..