Hi, I'm Bernard, a fellow Windows user. I'm happy to help!
I understand the issue you have. There is nothing to worry about. I am here to assist. There is actually a Microsoft Store installer that can be downloaded as .exe file. You can download it from here:
https://apps.microsoft.com/detail/9wzdncrfjbmp
Then click Download
It will download the Microsoft Store Installer.exe, then you just need to run it.
In addition, several factors might affect the installation of the Microsoft Store since you mentioned that the PowerShell command is not working on your end. First, there are several Windows versions, such as Enterprise, Education, or N version, which typically don't have a Microsoft store, depending on the permissions from your organisational IT.
If you are using a normal version of Windows, and the PowerShell command and the installer for Microsoft Store didn't work, I suggest doing an in-place upgrade, wherein it will update the device to the latest version and repair all issues without deleting any files.
Note: before doing this, make sure to create a restore point: https://support.microsoft.com/en-us/windows/system-protection-e9126e6e-fa64-4f5f-874d-9db90e57645a
- Go to this link: https://www.microsoft.com/en-us/software-download/windows10
- Select Download Now, and select Run. You need to be an administrator to run this tool.
- On the License terms page, if you accept the license terms, select Accept.
- On the What do you want to do? page, select Upgrade this PC now, and then select Next.
- After downloading and installing, it should fix the issue.
Reference: https://www.microsoft.com/en-us/software-download/windows10