Should use new, different NAS?

[Enquiries]

Have been using McCloud PR2100 for years with Plex. Now, with new Dell laptop and Windows 11, I am struggling to overcome Permissions issues with my Public folder of the NAS. Some files/folders are still accessible Read/Write. Others "You do not have permission, this container does not ..........". Talked to Microsoft tech, then to WD tech. This tech was able to make it work for half a day by making it Private, then Public again and by changing the IP address to 192.168.1.241.
Do I need to go to a different brand such as recommended by you, also with expanded storage, also Plex capability?