First let me say that fire fighting is NOT hard. But... Yes; there are some glitches & bugs that are very frustrating when they occur. But if you use all your options, then they are easily managed and in no way is the game unplayable. If it was unplayable i could NOT have built the ship i am using.

Engineers also do so, but from what i have seen, ONLY if they have no build or prior repair orders. Even some crew on assorted consoles seem to prioratise fire fighting, but dont rely on this. Even with a large crew of 40+ , its possible for fires to grow out of control if left to the Ai crew on your ship.

Note: i ignore trying to use the Colour Coded Warniing Alarms that alert the entire crew. From all my testing, they don't seem to help at all at fighting fires. Trying to rely on them is not a good idea.

Note : Currently in early access; the AI is not good at chosing crew near a fire, instead often times it picks a crew member very far away to fight the fire (or none at all if no crew are available, USE manual control. See below for mroe details)

note: If a controlled crew stops moving / working ; then most likely the pathing has become blocked from fire spreading. This will make your selected crew wait for new orders again.
Or that crew member is exhausted / starving ; in which case just release them and take control of another crew.
---------------------
Use inteligent ship design so that you can vent (airlock option) entire sections of the ship (or multiple sections) instead of trying to rush a crew to the area. Having multiple sections, makes normalizing oxygen mush faster. If your entire ship vents it can take a while for air to be breathable, quickly order everyone out in EVA suits while waiting if this happens. http://gtm.steamproxy.vip/sharedfiles/filedetails/?id=966498082 venting : 2 examples in 1 pic. Ir shows General crew racing to fires. The Food crew doing nothing (she need to have direct control to deal with it quickly-then release). My engineers were busy building.
---------------------
Sometimes a crew member will go to a large componant to try and put out the fire and then jsut stand there doing nothing even with manual control (happens in space also). Seems to be a bug, but it has a workaround.

Manually control the crew to move and stand directly beside the fire. This works to gain access to the fire to be bale to put it out. Very rarely, this still doesn't work, but if you move the crew to aproach the fire from diferent angles, it eventually does work.

This workaround fix has been confirmed by other players as working as of the last version
---------------------
good luck have fun

http://gtm.steamproxy.vip/sharedfiles/filedetails/?id=945392228 this guide really helped me out when i was starting. It has a lot of information and is being kept updated.

I recomend anyone who wants to learn more to give it a look.