I'm trying to speedrun Space Quest I and I'm confused if the timers are just there for an estimation? I ask this because the only way I've found to start the timer is to use hotkeys, is there a better way

Well to work the timer it would depend on which timer you are using. But I use splitty and We have blank splits to tell us how much time we take on a specific segment. And once you have your time done you can try to go faster and improve your final time. So I guess the final time I guess you can say is an estimate.

some games are estimates but most are there to verify mainly that you indeed beat the games in the time that you are reporting to have done them in. I use hotkey on my pc for some games but when I use emulators for others I map them to my controller. I use livesplit which I like due to great customization. I hope this helps