You cannot play Minecraft without a GPU, it's not possible lol.... The textures don't matter, the fact that the game is very un-optimized is why you need an okay GPU anymore. Sure you can get 150fps on the shortest rendering distance with optifine, but you're also running a UHD 620, which is a decent iGPU, comparable to a AMD HD 7750 of the years past. But again, look at any hardware logger and see the load on your GPU and CPU, and it will tell you everything you need to know.
Also, I think I know a little bit more than you, lol