Looking for a Reliable Thunderbird & MBOX Converter Tool

I am currently facing an issue with my email data stored in Mozilla Thunderbird (MBOX format). Due to a recent system upgrade and organizational requirements, I need to convert Thunderbird/MBOX emails into another format (such as PST, PDF, EML, or MSG) while keeping email structure, attachments, and metadata intact. I tried a few manual methods, but they are either too time-consuming, risky for large mailboxes, or do not support bulk conversion. Since this data is important for long term access and compliance, I am looking for a reliable Thunderbird & MBOX converter tool that is safe and easy to use. Can anyone suggest a trusted solution that works well for bulk email conversion without data loss?