Talk to him about it. As a GM I always ask my players at the end what I did right or wrong if they dont like my plots or want to do something different. Alot of the time my players tell me if the encounters were too hard or they didnt get a chance to do anything special so I change my plot for next session bc its about the players having fun not about my amazing super duper plot. Alot of times us GMs have good intentions but players dont speak up about the differences but just dont be too mean to the GM. If he does something blatantly stupid tell him but in a nice way and say how you arnt having fun bc of so many house rules or universe changes that he did. If he wont change or is just really mean to you I recommend leaving the group and ending it there.

An example of a bad experience is below

I had a GM who was causing my bounty hunter to be depressed bc the ship he was on with the rest of the crew hated him for no other reason than bc he wasnt a mutant or scum bc the rest of the group was. I told my GM about this but he just laugh it off saying if I wanted to I can always kill myself and role another character. So I legitly had to shoot myself with my stub revolver in the head . My GM didnt let my character die in some heroic fashion or sacrifice himself but instead made me kill him. That should never really happen unless everyone has fun with it but I wasnt and he was just mean to me so I left the group. Later I found out that he had my body made into a servo even though I shot myself in the head . Thats how bad my experience was with him and how much the group hated me for no reason.