Hello! The Ryzen 3 2200G is an entry-level processor with integrated graphics, so it may struggle to run demanding games like Genshin Impact at higher settings and frame rates. However, it should be able to handle Dota 2 quite well, especially with its integrated Vega graphics.
In terms of dedicated GPUs, the Zotac 1050 Ti 4GB is a decent choice for playing Dota 2 and Genshin Impact. It should provide smooth gameplay at 1080p resolution and medium to high settings. For Dota 2, you can expect a similar performance to what your brother experiences with that GPU.
If you're looking for an upgrade, you could consider the GTX 1650 Super or the RX 5500 XT, as they offer better performance for a similar price range. However, it's essential to check your power supply's capacity and compatibility with these GPUs before making a purchase. Additionally, make sure that your CPU doesn't bottleneck the GPU's performance.