Hey,
Recently I have been facing this problem and I got solution. So If you need to open EML files along with their attachments but don't have Microsoft Outlook installed, a dedicated EML viewer is the easiest option. EML files can be created by various email clients, and opening them manually may not always display attachments correctly.
A reliable solution is SysTools EML Viewer Tool, which lets you view EML files and their associated attachments without requiring Outlook. For users who need advanced capabilities, SysTools EML Viewer Pro & Pro+ offers features such as bulk EML file viewing, advanced email and attachment search, and export options to formats like PDF, MSG, PST, and CSV. This is especially useful when working with large collections of EML files and needing quick access to specific emails or attachment data.
Have you tried this software, if so, then let me know how was the experience. Thankyou.