This forum is an absolute gold mine. Here's another question.

[EarlG]

2. Unfortunately multitrack recording software is going to come with a layer of complexity

If you don't mind reading some manuals, you might want to look into something like Audacity (it's free):

https://www.audacityteam.org/

I'm assuming you're using Windows by the way. If you have a Mac, I believe the "Garage Band" app comes free with it, and does the same thing as Audacity.

The principle behind using this or any other multitrack recording software (you'll also see them referred to as "digital audio workstations" or "DAWs" ) is the same:

1) Make sure you have some headphones and a mic plugged into your computer -- yes, you can use the little sockets, if on PC the pink one is for the microphone, and the green one is for your headphones -- and make sure Windows recognizes them.

2) Run Audacity and figure out how to import an MP3 or WAV file of the song you want to play along to onto Track 1, then figure out how to arm Track 2 to record using the mic you plugged in as a source.

3) In your headphones you should be able to hear the music playing on Track 1, while the instrument you are playing is recording onto Track 2. When you're done, you can listen to them both together through your speakers.

That's it in a nutshell. Now, actually getting it to work might take a while to figure out. But there is a quick start guide for Audacity should should help you get started.

https://manual.audacityteam.org/quick_help.html