My foolproof method of avoiding jetlag won’t suit many people besides me.
1) Only fly on daytime flights.
2) Restrict flights to a maximum of 8 hours. Preferably more like 5 – 7 hours.
3) Book into an airport hotel for at least one night after each leg.
This works well flying either east-west or vv. It takes 4 days to get to and from Europe.
An example is
PER -> SIN (1 night),
SIN -> DXB (2 nights, could manage 1 night with time differences),
DXB -> FCO
Return
LHR -> DXB* (2 night),
DXB -> SIN (1 night),
SIN -> PER.
*At the time, EK had the only flight which left LHR in the morning, at around 0830.
Price was quite good as I flew on QF PER -> SIN -> PER on points and then EK from SIN onwards, the EK legs for only $1200 return. This was for the busy Dec. /Jan. period. A bonus was that we had time for a good look around Dubai, a destination to which I would not normally plan a visit.
Usually, I fly north/south on daytime flights so jetlag isn't an issue.