You can manually create the ops.json file along with the whitelist.json if you need it. The game will populate any changes to the file after manually creating them. I know because I have done this on Linux and Windows both.
I doubt with "op" you are going to get true op with a world with No Cheats and achievements on. It would be crazy if you could.
The problem is that the instructions do not say what flavor of linux to run the server on. Thanks for sharing that it runs on Ubuntu @Tanner!
This issue affects Debian 8 builds as well.
I don't see this as a bug or typo. You will get a random seed if you do not edit this before starting the server.
Most realm lagg I have experience seems to be from low end devices connecting. It seems to drag the performance to nearly unplayable to unplayable. There needs to be a way to handle this and Bedrock realms are not capable to do this at this time. This is a real issue with this version of the game. Although the concept is great (Better Together), performance wise the higher end products (Windows 10 and Xbox One) suffer because of the game trying to support too many low end devices like low specs. This is something eventually Mojang/Microsoft will need to fix or the complaints and issues will never be resolved.
This seems to happen dynamically unlike where you can set the min and max on java servers.