Troubleshoot Magento 2 errors

Hi,

We are looking for a developer to check our error logs and fix the errors with our website (https://greenheadshop.com)

There seem to be lots of mysql queries using up CPU resources and the site slows down.
Cron jobs aren't running correctly.
Occasional errors when just code is displayed instead of the website.

If we restart the server and clear cron backlog, it starts working again, but in 12-24 hrs it slows down and needs restarting again.

We need someone with good English skills so we can communicate properly.

Please see attached screenshots of some of the errors.

Thanks