No. File Explorer’s Size column cannot be changed from KB to bytes; Windows has no built-in setting or registry option for this.
For one file, right-click it, select Properties, and check Size. The exact value appears in parentheses, for example: 1.20 MB (1,258,291 bytes).
To display every file in the current folder in bytes, open the folder, click the address bar, type powershell and press Enter. Then run:
Get-ChildItem -File | Select-Object Name, @{Name="Size in bytes";Expression={$_.Length}}
This only reads the file information and does not modify anything.
Microsoft reference: https://learn.microsoft.com/en-us/answers/questions/2412074/display-file-size-in-bytes-on-windows-explorer