I might be able to save myself
I have a pretty good spy knowledge from lots of testing but have not tested this adjacency. I’ll try and have a look at it tonight. I very much doubt anyone but Firaxis knows because the testing is quite painful.
I do know quartermasters stack so why not others.... well because who would get promoted is an issue so maybe they just do not... so I suspect it will either add a level or more likely not at all as Firaxis seems lazy/cost efficient with coding.
In the meantime, if you do not have your l2 government building, get intelligence agency ASAP as that adds a level to your spies.
You are likely being hit hard in one city, if you have a save without mods I could identify where they are hitting you if you feel lost but it is very likely your largest gold place so you have a few choices, spread out your gold, this has a very good effect on diminishing what total they can take but does allow one particularly good player to take more (like Catherine)
If you keep it central, regardless of their spy abilities you will start capturing and killing with spies and this will level up your defensive spy which makes it much harder for them.
Use green cards that up your level also and any defensive promotions. Multiple quartermasters does help... also build an airport and harbour... it allows them stupid riskier escape routes.
EDIT:
Managed to identify that attacking spy adjacency makes no difference ...
(200 216 5 2659415619 sync Rolling Espionage Result)
defensive I am not suire I can test so will pass.