Try following this post of mine. You should only have one EXTRA_JAVA_OPTS, so just delete one and make it what is in that thread. If you raise the heap size too much you can force Linux to start using the SWAP file which is bad when you are running slow flash storage.
Run this command
free -h
and make sure the swap shows 0B as USED for the swap…
See the suggestions to look at the log files as you should diagnose what is wrong first before making changes to a system in the blind hope that you magically stumble on the solution.
The openhab.log file will mention “OOME” if you are running out of heap space from what I have seen…