Hi Nourlan,
Thanks for writing into the forum!
It sounds like you're on the right track here but I would point out that the packet loss doesn't carry through to the final hop whereas the latency patterns look very similar. This looks like this is a classic
bandwidth saturation pattern. If this is new then there is likely an issue with that 2nd hop and your ISP will have to look into it.
Here is an article on how to build a compelling
case with your ISP.
Let us know how it turns out and if there is anything we can do to help!
Thanks,
-Poe