I have been working on slowly making my vera plus just a bridge due to its hardware limitations, disproportionately overambitious integration and poor core software development.
As the next step in this journey, now that I have absolutely no plugin integration requiring internet access, I have decided to block all internet traffic to and from the vera unit and see how it fares and wanted to share my experience and maybe get inputs from people who have already done so:
1. First thing to do is to disable the auto-update from the apps which are left. For me it was easy as I only have ALTUI, System Monitor and one instance of the countdown timer left.
2. Ohh I forgot those 2 absurdly useless plugins from vera: The Sercomm IP Camera and the Amazon Alexa Helper. I tried deleting them thinking they could not be re-downloaded after my vera has no internet access. Well I was right but the vera after about a minute post luup reload tries to get them again, post an "error in scene or plugin" in the luup task bar (The blue message bar) and I discover that it disables its network socket. Basically all scenes continue to work unless it is required to send anything over http. The log shows that there is an AutoPluginInstall function which failed. I decided to let it redownload them and now I am seeing
This plugin is automatically available on all Vera controllers and does not need to be manually enabled.
on the "my apps page" for these two plugins. I can't say I am pleased. MCV: Your hardware is not capable of handling all the integrations you are throwing at it. Please allow your customers not to download software they do not use. Or if you want to do so, upgrade your hardware by 2-3 generations on memory and CPU. Heck, my coffee machine has more processing power and memory than the vera.
3. The vera seems to be... less prone to random luup reloads. I am running the bet 26b firmware.
4. My access through VPN and Homewave to the vera is now much faster through VPN having bypassed the mcv cloud server.
5. No more "your vera is offline-online" nonsense. It is permanently offline

6. I setup all my notifications through Homeassistant and Pushover which is much more reliable and has less latency.
7. I think the system is more secure now having cut off one uncontrolled access path to my home.
8. Great reliability improvements overall as I won't have unwanted downloads onto my Vera updating files sending data etc.
9. I lose the daily automatic backup and log transfer... So I have to backup locally and log onto a USB stick.
10. As many people already know here, keeping time between reloads is a big issue for the vera. I did set it to read time from my local NTP server so it doesn't need to access a public NTP. What puzzles me is, the vera updates the user json file regularly. It is how it is able to remember status of devices between reloads. Why not get the time from the last modified date of the user json file by default before going for the NTP server??? At least it won't be off by 19 years.
Overall pretty happy with the outcome and I may keep it longer than I initially thought if it stays this way.
Update: For those who want to go straight to the point. I have posted the script files and instructions to implement this in post #175 and #176.