Really glad to know that the problem has been solved. We sincerely appreciate you sharing the solution to the problem.
By the way, since it is the policy of the Microsoft Q&A community that "question authors cannot accept their own answers" and in order to better archive cases so that other community members with the same question can benefit from them as well, I would make a brief summary of this thread:
[One user cannot search nor edit items in a list]
Issue Symptom: A member of a SharePoint group can't edit and search for items in a list, even though he has contribute permission level to the list and edit permission level to some items.
Current status: A problem with a user's permissions to another site is causing the problem. The local helpdesk then renamed his VDI profile and his new zero client session was working properly again for both SharePoint sites.
You could click the "Accept Answer" button for this summary to close this thread, and this can make it easier for other community members to see the useful information when reading this thread. Your contribution is highly appreciated.Certainly, if there is anything else I can do for you, please do not hesitate to reach me.