It doesn't matter if you eat protein powder after dinner, especially in the muscle building stage.
Your time is also reasonable. Exercise starts at 6 o'clock, and at 7: 30, which is similar to the protein powder you drink within half an hour after exercise, and the effect is the best. Moreover, the heat of dinner food just supplies the loss of muscle movement, so that protein can use it to grow muscles. After exercise, because my home is far from the gym, I will eat some sweets like chocolate to supplement my energy, then drink protein powder, and then go home for dinner.
If you are in the stage of reducing fat, you can have dinner first, take a break before exercise, and add protein powder for half an hour after exercise.
Please note that drinking plenty of water every day can ensure normal metabolism and more adequate absorption of protein powder.