Overclocking and undervolting is a process that takes time because you need to try upping or lowering small increments every time, check for stability running games and benchmarks and if stable, up or lower again and repeat.
There is no guarantee that you will reach that clocks. You may buy 10 3060 ti's and every single one can have different results.
Since Nvidia uses GPU boost, the best thing you can do is to have the card run as cool as possible and it should achieve higher clocks. Basically if there is enough power and thermal headroom, the GPU will boost higher.