When to lateral? Any tips to survive (insomnia)?

Dear community,

I had mastered technicals and managed to network my way into a world-renowned top-tier EB (a clear #1 in the region of the world I live in). After the stint, I will be doing a MSc in Finance at a decent university (with quite good placement in London's BBs). I got 8 months of experience at a BIG 4 firm, too.

The thing is that my GPA is too low to even be considered for an interview at top shops in London so I will just do my best to secure the FT offer at the EB I got into. I plan to live the "FILO rule," namely the first in last out for the following 2-3 months so let's assume I do manage to get a FT offer (conversion rate is terrible and they do take like 3 interns a year so hours are reportedly really bad - dealflow is insane and deals are big, yet smaller than typical deals you could expect at a BB firm).

If I graduate 4.0 cum laude and kill it for another two years at the EB, would it be feasible to lateral to top shops in London (Lazard/BAML/GS) as a 3rd year analyst (2nd to 3rd)? Please note that I don't see myself in private equity, and I think about banking long-term. Maybe I don't see the obvious option, and it's easier to lateral later on: as a 3rd analyst from the EB to an associate in London?

Also, there's no adderall in my country, any tips to survive 100-110 hour weeks for 3 months and still kill it? I suffer from insomnia and it's hard for me to fall asleep in less than 2 hours in bed, but I can live on 2-3 days without sleep. Can I take advantage from this?

Please be serious and thank you.