If this is a single tenant I don't see the issue. Where do you find the requirements for more than one accessible restroom if both are "gender neutral"
Th 2021 attempts to address this and if you have not adopted it yet I suggest you use it for guidance and possible approval under
[A] 104.10 Modifications.
Where there are practical difficulties involved in carrying out the provisions of this code, the building official shall have the authority to grant modifications for individual cases, upon application of the owner or the owner’s authorized agent, provided that the building official shall first find that special individual reason makes the strict letter of this code impractical, the modification is in compliance with the intent and purpose of this code and that such modification does not lessen health, accessibility, life and fire safety or structural requirements. The details of action granting modifications shall be recorded and entered in the files of the department of building safety.
2021 IBC
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