I have been playing the modpack ATM10. It seems there is a strange interaction between this mod and AdvancedAE.

I have already raised a ticket with the developer of that mod and they advised me to raise it here too.

Here is my documentation of the issue with generated reports from the game that show your mod is related to the issue: https://docs.google.com/spreadsheets/d/1ee_r-STM2SdC2wr7Pvm0FyTSaUfMfaTcwp3SAu9Whec/edit?gid=0#gid=0

Here is my discussion and issue with the other developer: pedroksl/AdvancedAE#237

On the server where I have the issue, I have not interacted directly with any Eternal Starlight content yet.

Everything is fine on my side even when I'm wearing a full set of quantum armor with full upgrades, but I suspect that some armor check that happens every tick in eternal starlight's code may have triggered a chain reation (especially on a super-large modpack like ATM10) that caused the lag. I'll try to use a simpler way to implement these armor checks.