No. There is no free solution to this problem. The reason is that Outlook stores every content in the most secure format. Therefore, it is necessary that exported OLM files be migrated to a separate file format with the same care.
I used a couple of tools. The first one took almost 25 hours to convert just one GB of emails. My Outlook is as big as 8 GB. He had to reject the tool immediately. He lost money too. Now I tried to find a tool that could offer a free trial tool before purchase.
I found OLM Converter Pro and this was it. Let me convert ten emails from each folder almost in no time. The conversion accuracy was also remarkable. I ended up buying this tool. This is worth trying. https://www.gladwev.com/portfolio/olm-converter-pro/