Is there a addon that can view the memory usage of each addon separately?
 

I often observed a significant decrease in my fps during my trials, while the total memory usage of the addons significantly increased. I assumed that there was a connection between the two, and wanted to get the real-time memory usage of each addon so I could troubleshoot.

However, my simple search did not find any addons that could fulfill this requirement. Is it possible to achieve this?

afaik there is no way to detect that by any given lua or ESOui lua API or function.

And your FPS decrease most likely happens the longer you play. Try a /reloadui here and there and it should free up ressources, like created controls and other lua objects, internal tables, map pins, markers in inventories etc.
They should be re-created then once you really need/use them.

I'd also disable just addons you do not need like raid addons at overland, and vice versa. Carfting related stuff if you quest.
Price related addons (or libs like e.g. LibHistoire) and guild addons if you are doing dungeons, overland quests.
And so on.

You can use Addon Selector to create profiles to easily change the addon packs depending on your needs. The more addons enabled, the more lua operations are done, the more controls get created, the more lua tables stored and updated, the more memory consumption, the bigger the SavedVariables get, the longer the loading times, ...

Thanks for the explanation Baertram. Looks like I'll have to find another way to solve the fps reduction problem

Do you think this is possible? :
- Addon authors add a few lines of code with a trigger to completely bypass the addon
- Once triggered via a chat command, a memory analysis addon use the code to bypass addons one by one to compare collectgarbage() and collects stats.

That's sadly not how it works. You can't just "bypass" an addon and quickly check how much memory it didn't use. It's a bit like throwing different ingredients into a bowl and stirring them - you can't just take out an egg after that.
You'd have to completely disable an addon, reload the UI and then somehow restore the exact same conditions you had before the reload, otherwise the memory consumption may be different due to other factors.

That aside, memory consumption does not directly correspond to FPS loss anyways. If you want to find out which addon is causing your game to stutter, you could give ESO Profiler a try. Just wait until you encounter the issue, activate it for like 20 seconds and then export the captured data for inspection in the external viewer. That should hopefully give you a clue which addon is eating your frames.