Discrimation while working in japan as an international student.

I came to Japan in 2022 and worked at a combini for about 3 yrs. During that time, i was usually the only foreigner working there long-term..
Something i noticed early on some customers would act rudely toward me but when the same customers spoke to my japanese coworkers they were very polite. I tried my best with keigo, and they still talked down to me. Most of the times the rude ones are older people so i thought the new generation is not like that. But that is not the case. Also after the recent election slogans like "nihonjin first" "foreigners live off japanese taxes" japanese people 's attitude got worse.
I had a 20yrs old coworker who constantly bullied me i was 25 at that time and he was also 8 months junior to me at work also not just in age. Yet his position was a bit high and he used to use words like "omae" but i was told to use "san" after his name. One day i asked him to pass me something and he said i should do it by myself instead of making my seniors work for myself so i asked him you are not just my senior but also a coworker to help me, i am not asking you to help me for my personal problems. And the other Japanese man in his 40s did not like that i talked to a Japanese person like that and he scolded me so badly. Later i worked for 3 more hours and while returning home i went to the public restroom in train station and cried for some minutes. One day at school when i was laughing during class hour (i know i am the bad one this time i broke the rule) a teacher said something very disturbing.. he said if you wanna laugh go back to your country. He could have said me in a different way i understand it was my fault but still he is a teacher could have taught me in a good way.

Last one,
One regular customer constantly harassed me, even calling me baka for no reason. Once i politely asked him if he wanted his croquette heated (コロッケ温めどうされますか) he literally asked me are you a student and i said yes and he said why is japan accepting brainless people? Can you really study? Do you think people microwave croquettes? (Yes, many customers do)
Last month (august's first week) the same customer came and as usual he kept on yelling for no reason so i said please go out or i will call the police and he got more mad and kept on yelling call the police go on. But i know things will get worse for me so i backed off again. Next day tencho called me and said there is a complaint from customer and yeah i was fired for that one time when i tried to take stand for me.
And after few weeks i found a new job at new place and on my 4th day, a very young looking guy tried to buy seven stars ciggaretes i asked for an id (as required by Japanese law) he hot angry and started yelling infront of other customers "look at my eyes. Do i look like a kid? Talk to me" he was young everybody can tell that but let's even if i misjudged it is a rule made by a Japanese person for the safety of Japanese person right?
There is no reason to bully someone who is helpless and cannot sell you ciggaretes because of the law of his own country.
Idk what should i do next because i am really started to feel bad these days and until my graduation there is still 2 years i am already scared how many more times i am gonna have to face this things.

by Necessary_Throat_343