Hi @Srini VSP ,
As far as I know this shouldn't be possible using Powershell. It’s very easy to export “who has access to this particular resource” but much more difficult to export “what resources does specific have access to?”
I tested the code provided by Tasadduq Burney , and the output of this PS code seems to show that I have access to all site urls in the teanant (as shown in the figure below, it shows that I have access to the site "test1232", but actually I cannot access ). Even I can help you to modify the PS code to make it output to csv file.

I found a discussion with the same requirement as yours ( Possibly achievable via MS Graph or other methods), you can check it out:
https://www.reddit.com/r/sharepoint/comments/10eob9v/list_all_sites_a_user_has_access_to/
Maybe you can take a look at this, this approach also meets your needs.: Use Search to List All the Sites You Have Access
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