No, it is not true.
https://browser.geekbench.com/v5/cpu/2748062.gb5
"processor_frequency": {
"frequencies": [
2493,
2493,
2493,
2493,
2493,
2493,
2493,
iPad:
https://browser.geekbench.com/v5/cpu/2757729.gb5
"processor_frequency": {
"frequencies": [...