Low FPS/Lag issue in 1.19.4

Hello ! I am currently in the creation of a Wynncraft modpack in 1.19.4 I used it for a while without any problems, my friends used it too for a while.

One of my friend that used to play with it has recently got his SSD changed. Soo he lost all his minecraft instances. Yesterday he tried downloading the modpack and play. When connecting he notices fps issue.

I obviously told him to :
- Lower his render distance
- Check for minecraft quality settings
- Check if block culling works
- Do /toggle ghosts none

He tells me it got little better (from 10 to 30)

I asked him to help me debug with shift+f3 and we saw that the lag issue are cause by "entities" but we don't have any more infos....

I was wondering if you know else :
What could be causing lag and how to fix ?
Or if you know a better debugger for the client ?

The weird thing is that I don't lag and most of the lag caused on my client is because of world Render (I may have taken my render distance too far (32Chunks))

If you want to know the mods I use and the config you can check "enzomtp's Wynnpack" in version "2.0.8" on modrinth

Thank you un advance
Your cordialities
-enzomtp

 

For reference my friends specs are :
CPU : Intel I5 (i don't know which gen)
GPU : GTX 1650
RAM : 8Gb (not sure) DDR4 2666mhz
With a samsung 980 pto 2To for the upgraded SSD

And i have:
CPU : Intel I9-13900K
GPU : RTX 4090
RAM : 64GB

So i do excpected a lower frame rate than me but not that much !