The Table To Excel tool replaces values with Chinese characters when a value or part of a value in any element of a table matches the regular expression.
There are not going to be any further ArcGIS Pro 2.9.x patches.
Given that the issue is not reproducible in ArcGIS Pro 3.0 and 3.1, as well as in the current development version 3.2_48723. This issue is closed. It is advised to migrate to the latest released version of ArcGIS Pro. If it is a must to remain on ArcGIS Pro 2.9.9 and this issue halts the work, contact ESRI Support to make special arrangements.