My mother passed on 12/21/2024, and I have an EIN to setup my Generation Skipping Trust (GST); no bank account is setup nor have I received income; is Form 1041 required?

[M-MTax]

Not required until the trust actually receives income/gain.

See https://www.irs.gov/instructions/i1041#en_US_2024_publink1000285943

You ARE going to need a lawyer for this.

I am sorry for your loss.