The "Other Gospel" that Paul went against and warned people about was any gospel that combined Grace and works. We are saved by grace plus nothing. The work Jesus gave His people to do was the works He did. He said Isa. 61:11 The Spirit of the Lord Jehovah [is] on Me; because the LORD has anointed Me to preach the Gospel to the poor; He has sent Me to bind up the broken-hearted, to proclaim liberty to the captives, and the opening of the prison to those who are bound;
2 to preach the acceptable year of the LORD
This He read to those in the synagogue Luke4:18 The Spirit of [the] Lord [is] on Me; because of this He has anointed Me to proclaim the Gospel to [the] poor. He has sent me to heal the brokenhearted, to proclaim deliverance to the captives, and new sight to [the blind, to set at liberty those having been crushed,
19 to proclaim the acceptable year of [the] Lord.
I doubt that I'll get part of that $10,000, but I won't turn it down.
Your closer but no cigar. Isaiah 61:11 defines only the first aspect of the Great Commission -preaching the gospel and its effects. The second and third aspects of the Great Commission go beyond mere evangelization of the lost.
You are correct that the "another gospel" refers to the gospel of works as there is no gospel that is works plus grace because they cannot be mixed (Rom. 11:6). So there is the gospel of works that masquerades as grace or the gospel of grace.