Heroku, internal server error, Error R14 (Memory quota exceeded)
The ram usage of your application has exceeded the available qouta since you are using free tier, the memory qouta is 512 MB. if you see the log, 2nd last line it states mem=805M. No upgrading to hobby will not resolve the issue as it has also 512 MB memory qouta.
you can refer to this link for more details
https://devcenter.heroku.com/articles/error-codes#r14-memory-quota-exceeded