Tried all of them :)
Then I setup the development environment, since I have the apollolake (new ds918+ and first synology), I could give it a try:
-I was able to compile nano, duplicity, ...
-With tvheadend the openssl error was easily fixable, but the tribidi thing was a step to far for me. :) (changed from download to github and prob other verions)
So I tried the docker way,
which worked!... for a while...
Suddenly website was not reachable anymore, same problem as before.
The docker was running fine, could see the process, open ports. Docker itself forwarded its port perfectly.
Looks like non standard DSM port get blocked.
I decided to leave it as is and get some sleep :)
In the meanwhile, I saw that overnight the update 5 was installed, and yes my tvheadend website is reachable again!
I suppose there is a protection kicking in or rules are getting erased for whatever reason.
If it happens again, I think I should look into the qnap iptable rules.
Thank you!