I don't see that being generally true. For example, the Toyota Mirai weighs 4300 lbs to the Tesla Model 3 weighing 4000 pounds:

https://www.caranddriver.com/toyota/mirai/specs

https://www.caranddriver.com/tesla/model-3/specs

As far as acceleration, that's just a design parameter, as both are driven by electric motors. I'm surprised the Mirai can't perform better given it's extra weight.

Mirai can't perform better because the fuel cell can't put out enough burst power, it needs a buffer battery as is for acceleration and regenerative braking and the buffer battery isn't big enough either for Tesla like acceleration due to size and weight constraints.

The Mirai offers more range; it’s not apples to apples. FCEVs do have some constant overheads around the fuel stack weight.