First, there was not a 2600G. There was a 2200G and a 2400G with Vega integrated graphics. There was also a 2600 and 2600X without integrated graphics.
Second, it's not possible to "disable" the integrated graphics on a processor. Yes you can disable integrated graphics with a motherboard BIOS setting but if you move the CPU to another board or reset the board settings it is automatically re-enabled.
Ryzen R7 5700X | B550 Gaming X | 2x16GB G.Skill 3600 | Radeon RX 7900XT
Ryzen R7 5700G | B550 Gaming X | 2x8GB G.Skill 4000 | Radeon Vega 8 IGP
Ryzen R5 5600 | B550 Gaming Edge | 4x8GB G.Skill 3600 | Radeon RX 6800XT