The pilots on lion 610 were in regular contact with ATC and as late as 20 seconds before impact with the ocean they indicated their preferred flight level. This suggests they were not under duress in operating the aircraft until the very end. It is still very much unclear why their successful and consistent NU trim corrections are suddenly insufficient to counteract MCAS.
doesn't that lead to a presumption that the aircraft speed was decaying to a point where lift on critical surfaces was lost?