I just took a screen recording to show how slow Joplin system going when I update a tag which with hundreds of notes as shown as attached video.
BTW, the method that I am taking now for renaming a tag is as below:
Create a new tag based on old tag name modification
Select the old tag
Select all notes of aforementioned old tag
Adding new tag to selected notes (This is the part taking a lot of time)
After adding tag to all notes completed, delete the old tag.
My guess is that someone would be curious why I did not just rename the tag directly, I know that is how things SHOULD go, but I tried it last time (and the slow-process in attached video is the same in this method, if my memory serves me right), and then my Joplin tag system gone messy (Reference link1 and 2) and I had to reinstall my Joplin system... Hence, I now sticking to a work around like this.