What methods are suitable for estimating the noise level or as a noise_level_model?

[Zhao-Shi-jie]

This is an outstanding job, but I still have a question regarding noise_level_model.
Now there are various noise level estimation methods, including those in the spatial domain, frequency domain, and based on deep learning, and so on. The scale of the results obtained by applying different methods to estimate the noise level on the same image is greatly different, In practical applications,using them as noise level estimation models can make the effect vastly different.; so what method should be used to estimate the noise level in DPIR(noise_level_model) is the most suitable?