Time Machine will start to back up but then it will often stop before the backup is completed.

Aha!

Low disk space - This computer is running critically low on free hard drive space.

Filesystem: APFS

Mount point: /

Used: 239.25 GB

Shared values

Size: 255.85 GB

Free: 12.70 GB

Available: 12.71 GB

Free up another 20GB of space, especially since you have so little RAM!

Try one of these two…

You can use Drive DX to possibly get a better view of Drive health…

https://binaryfruit.com/drivedx

Thanks to Jack-19…

It may be wise to run SMART Utility to check the drives' health. 

Hi there... any error messages when it quiys?

We need to see what all is running, a report from this will not display any personal info...

Using EtreCheck - Apple Community

EtreCheck is a FREE simple little diagnostic tool to display the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support Communities to help people help you with your Mac. It will not display any personal info.

https://www.etrecheck.com/

Thanks for Old Toad’s etrecheck instructions…

Slow iMac 2017 - Apple Community

Use the Note tool on the bottom of this editor's toolbar, as shown in the image, to copy and paste the output from EtreCheck. In a Reply before you click post, look for this to add longer texts...

Easiest would be Find Any File...

http://apps.tempel.org/FindAnyFile/index.php

Hold Option or alt key when selecting Find to Find All.

For instance...

Great to hear my friend! :)