Actually, I have been utilizing Docker to run several OPENHAB instances side by side. However, I have stopped it to rule out this as a root cause for my memory problems. The reason is that the OH web interface seems not to be designed for several instances even though different port numbers are used. Something with login token.
And it is not so easy to just spin up another instance to run the house while debugging. After all, they point to the same hardware devices and not all can handle e.g. 2 clients logging in at the same time.
Others seem to have similar problem in Docker - see here