Should I get a Japanese license?

Hey there, I recently arrived in Japan and have recently been driving with the JAF translation of my German license. Some car rental places in my area only accept Japanese licenses, so I am considering getting a Japanese license.

Do I lose my German license if I get a Japanese one? Many online sources use “conversion” or “transfer", implying you give up the original license.

And second, after my year abroad I will leave Japan for a while again but will return likely within 5 years, however, Japanese licenses seem to expire rather quickly compared to German licenses. If my license expires while I'm not in Japan, will I not be able to renew it on my return?

Thanks for your input in advance!