I think you underestimated the GPU in the M1 chip. There are reviews out there where it is capable of gaming at 1080p on games like Shadow of the Tomb Raider. In games that it can run,
it is possible to get close to a dedicated card, and easily outpacing the Vega 8 and Xe graphics. You can see the bench results as well as Rise of the Tomb Raider being tested on 1080p on high graphic setting running with extra overhead from Rosetta 2 since this is not M1 optimised.
www.anandtech.com
I don't know if 1 extra GPU core is worth the 200 bucks with say an 8GB RAM upgrade or storage upgrade. Haha. Its an added incentive if one decides to upgrade RAM or storage.