Short answer: No.
The feature to load remote content only after the user allowed it, is mostly implemented to protect your privacy. Of course there are effects like less data usage and maybe some people do not want to have so many images in an e-mail, but the main reason for this feature is data protection.
When there would be a way around this (a feature for you as sender and person who wants to track the e-mail), this would be a bug in the protection feature and the mail program developer would hopefully fix it as soon as possible.
So what you're asking for is a hack or exploit, that allows you to circumvent security measures in the client software. There may be answers for specific softwares, but all of them would be security bugs in the software and may get closed sooner or later.
Is there a way to track emails undetectably, so no one can detect that emails are being tracked?
Don't you think, that this behaviour is kind of sneaky? It may even violate GDPR.
If you want delivery reports, just ask the user for it.
There is even a feature in the e-mail standard for it, that should be GDPR compliant, because the standard says, that e-mail software should ask the user before sending the report. If you want an unified UI across different mail programs, add a link "Please click here, to confirm that you received the message".