I was under the impression that every three weeks the neighborhood changes up,
*two weeks
yet for the past 4 cycles I have the same rat bstrd plundering me
You will have some neighbours remain the same between neighbourhood cycles, it simply updates.
Your placement is based on progress on the technology tree. If other players change their progress, then you position is adjusted. If no one makes progress, then there's nothing to change other than shuffling those with the exact same amount of progress.
'cuz that's the only way to get away from this a-hole. I've kept my city shield up for many weeks now
Everything Motivated is 100% immune to plunder
Your best asset will simply be getting things immune to plunder and ignoring whether you're attacked.
Also anything that's a Random Production building should be immune to plunder (without needing Aid). This would be things like Crows Nest, Pirate's Hideout, Druids Temple etc.
The Guild Battlegrounds buildings are also immune.
Buildings that automatically age up (they appear as "All Ages" prior to being placed in your city) are also immune.
You'll want to limit any Supply Production buildings to a 24-hr production to limit the amount of Aid needed. Residential Housing you can limit yourself to only collecting once per 24-hrs if you need to reduce the amount of Aid needed for your city.
You'll also want to work on having a active friends list, and only using your Self-Aid kits when you're not getting enough Aid.
Chain-Link buildings. These usually don't need Aid to produce. This puts them way down in the Aid priority list. Make sure the main building is your current Age, and any attachments remain in the Age you obtained them in. This will redirect the Aid to the Main Building.
Alternative methods to obtaining resources: If you're unable to reliably collect your unaidable buildings at a set time each day, I would suggest you focus on transitioning to anything that provides the same resources that can't be plundered.
So instead of Goods Buildings (these can't be Aided, and are able to be Plundered), you may want to focus on Quests for your main source of goods in conjunction with any Special / Event buildings that can be Aided.
With this in mind, your Supply Production buildings put on a 24-hr cycle can be used with the Recurring Quests to generate goods. And they can be Aided to protect them