JEE Main

You can use the Shiksha college predictor. You will get the college on the basis of your rank only. Hence, these predictor also uses the tank secured by you. I am attaching the link please check it out:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor
For any further query, please feel free to ask.
Best of luck.
If you like my answer, then please press thumbs up!

Within the first 30000, you can ensure seats without any problem. If it is above 50k, its totally impossible.

NATA is important for B.ARCH admission. Without NATA, your drawing skills and ability to go for architecture cannot be evaluated. So, its not possible with JEE only.

Sorry to say. Its a bit difficult. The reputation of the campus is very high and it will be difficult for this score.

If it is 45 rank, you can. But if it is 45 marks, it will be difficult. If you want to know the college list, kindly check below based on your rank:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=connect&utm_medium=CR_JEECP&utm_campaign=4479470.

You can ask for such questions in the CBSE website. All the grievance will be solved through them only.

If you have any grievances, you can complaint to the concerned mail id given in the CBSE website.

Yes, you can. If you can write state entrance, you can take admission over there.

You can look into the below link which all colleges accept JEE score:
https://www.shiksha.com/science/articles/colleges-accepting-iit-jam-scores-ranks-for-admission-blogId-13971.

You can get state government college in lower branch. For more details, please mention your state.