An advice from an expert person that has no girl friend since birth...
No love for me in this world
But my LOVE/wife exist in another world
And Isekai is real (In theory)
Because When you die
Your brain will trigger it's 100% potential (It takes only 1 sec or less)
which then transfer all your data to another possible world with the same wavelength as yours...
And YES the thing they call as the "SYSTEM" is nothing but your brain which is in max level that will support you through all your journey to another world...
And The reason why most Isekai MC has thick PLOT ARMOR and was almost invincible is because that another world it technically their own heaven...
Take note after you die in another world it means you are really dead in your original world...
As your SYSTEM(BRAIN) can only help you if your original body is still alive..