That’s so frustrating especially when Bitcoin reached almost $70k, but I don’t think there is another way to recover your investment. I have a friend who also lost his private keys and couldn’t find the written private keys too. So sorry for what happened to your PK, hopefully you’ll be able to recover them and if not I hope you are able to move on past it and probably invest again; learn from your mistakes.
Yes, I hope he can still recover his wallet and be able to sell it now. All of us especially for those people that know about cryptocurrency way back 2017 when the cryptocurrency is not popular as it is now. I have also got some good money now if I'm not sold it at low price compared today but I'm not regretting it since that money I was be able to graduate and help my family with some of our needs. It could make me rich and be able to start some business today but it already happened and I just look forward and start again earning as much as possible so that I'm not be able to missed it again.