iOS 16 or 17/18 (14 Pro Max)

So I’m in a situation where I can’t decide if I should stay on iOS 16.6.1 or update to 17/18. I’ve had this phone since the beggining of 2023 (97% health), kept it on iOS 16 due to fear of bad battery life on newer versions. Is it safe for the battery to update or stay on 16? Will it last the same on 17/18? Please I only need answers for my questions. I don’t care about security and anything else, just the BATTERY because I never had any issues, the phone runs perfect as is but I just got bored of it and I thought maybe the update will make me want to keep it for longer.