Query regards to Confirmation Letter & Probation Letter

My probation is over, and the company has issued a Confirmation letter. The notice period during the probation period is 1 month, whereas after the confirmation letter, my notice period will be 3 months. Additionally, I am on contract for a Government project (Contract-to-hire) for 2 years.

So, my question is, is it mandatory to accept the confirmation letter? I am currently searching for a job and have not been able to find opportunities with a three-month notice period. There are no signs of a reduction in the notice period.

Regarding arbitration or dispute agreement, I am happy with my job despite working 10-11 hours.

Normally, no acceptance is mandatory for an employee on probation. It's good enough when you accepted the offer of appointment and the appointment order upon which you joined the firm. It's deemed to be accepted as you are continuing the post as of now. NP of 3 months also not open for dispute as such stipulation is in vogue commonly.

I couldn't guess what should be the clinching factor to decide in favor of a project which can go for 2 years only 'on contract' unless you are a contractor and expecting huge income from this. What if, for argument's sake, your position becomes bad in conclusion of the project? I'm afraid you'll have no favorable point to overcome 3 months NP.