Harryb2448's suggestion is a good one. Unfortunatly this does mean the purchase of a USB external HD preferably with more storage than your Macintosh HD. Say you have a 128Gb Macintosh HD then a USB external HD of 250Gb would be ideal. It should be a dedicated HD so that incremental backups can be made. Once you are satisfied it is complete and bootable you could even erase your old Time Machine HD although I like to have both.
The huge advantage of a bootable clone is that should you lose or damage your computer you can boot another Mac laptop with your clone and it will be just the same as your computer. All your files, your Operating System, settings, preferences and applications will be identical to your computer at last backup. Apart from this obvious advantage you can also use the clone to restore all of the previously mentioned data to a new HD or new computer eliminating the need for Migration Assistant. No setting up iCloud, email, browser sites, application settings, passwords etc,etc.
I personally chose Carbon Copy Cloner by Bombich Software available here
https://bombich.com
Super Duper is also good. They are both about the same price and both offer 30 day free trials which means for your purposes it will make a free copy and if you like it you can buy it later.
My wife's Macintosh HD died a couple of months ago so she ran her MBP off her Carbon Copy Cloner backup for two weeks while we awaited the arrival of a new drive. Once the new drive was installed she simply restored her data from the clone onto the new drive and was back up and running in a hour. It really can't get any easier than that.