I’ve done that trip many times (with other adults) and for me 1yo would be the worst time to do it.
I did do some long haul at that age but with DH and it’s hard work.
Baby is big and you aren’t guaranteed a bassinet as younger babies will be prioritised. They may be too big to sleep in there anyway and they will be big on your lap (armrests don’t lift in the bulkhead seats on any airline I’ve been on so extra hard to sleep them across your lap). You could pay for an extra seat for comfort. You can’t leave a mobile baby like that alone for a minute which will be taxing.
Baby will be mobile and wobbling up and down the aisles.
Will be getting big for the tiny change table.
Will need lots of food and snacks. Usually none at all provided for a child that age.
It can be done but it’s very hard work.
If you did I would have a baby zen yo-yo stroller.
In my experienced (done this trip many times with my own baby and toddlers, and before that did it with my sisters’ kids) opinion, the best time is a few months old- a 3/4/5 mo old baby is vaccinated, not mobile, doesn’t need solids and easy to sit on your lap, can defo fit in the bassinet.
I then do it again around 2 yo when they can walk very steadily, eat a regular kids meal, and engage with a screen for a longer period for entertainment.