Should SE scale high end content difficulty towards the usage of SIM ?

[VerdeLuck]

IMO, they should 'air gap' (from their network lol) a PC go and tell someone to download and use a boat load of the third party addons, even the ones that come from custom githubs. Make a list of them based on popularity or interesting features, attempt to add any that are reasonable, and then contact the addon creators ask them to create a list of features they would need / like (officially), make that, begin to ask addon creators to move to the official system and start to create ways to catch unofficial addon use and punish it.

This would not work, the most popular addons are splatoon (shows aoes that game hides on purpose), ACT (damage meters, complete no go), and Cactbot/Automarkers (Adds markers to mechanics where the devs purposely don't add them over your head).
Most of these mods explicitly exist to undo design changes that the devs do on purpose to make it harder via obscuring information or making it harder to clearly find where to stand to be safe. In the same way Ultimate's entire difficulty is derived from priority mechanics and the consistency check of needing to be good at the start to prog the next phase.

Adding or using simulators and boss mods completely removes the conscious design choices the devs made to give you that difficulty. If anyone uses these mods they are at fault if they find it too easy. You are purposely undoing the design choices to make it easier to clear.
So short answer is all they can do is make things clear enough that people can clear vanilla and if players use tools to speed up their own farm and prog, then tough shit for them specifically. If you were to implement them then all content would just be "don't stand in the orange" at every single difficulty.