I have a video that has some unnecessary text that appears several times while the video is playing.
I tried to blur (censor) the text using the 'Eight-Point garbage matte', 'Gaussian blur', 'Mosaic'.
Also tried 'Track Matte key' with other blur effects. Also tried changing the blend mode.
The problem is, it creates a clearly visible white border around the blurred portion and it doesn't look nice.
And the border is more visible when a bright video is running behind it as seen in the below screenshots.
Any advice to get rid of this problem would be greatly appreciated. Thanks.
Garbage matt + blur is likely your best bet. Results will not be great.
If Premiere had better feathering tools for sculpted layers\tracks, it might look nicer. If your created a .psd in Photoshop, with a feathered alpha channel matte shaped to obscure the text, a track matte could work best if you understand how to employ it.
Have you tried doing a Feathered edge on the Matte in Track Matte Keying?
Otherwise, I think that the Clone Tool in AE might be useful - provided that you have enough background to Clone from.