My 3DS won't read my R4 card and neither will my other DS

My R4 3DS SDHC Gold Pro stopped working back in May 2019, and I kind of left it sitting since.

Now, I’d like to use it, but it just won’t even show up in the home menu. This is happening on both my New Nintendo 3DS XL, my Old 2DS, and my Nintendo DS Lite.

Is there a problem with the card? Is there a chip I need to solder on/off?

Is it a time bomb? I’ve heard of those, but nothing like this.

I opened GodeMode9 in my Old 2DS to see if it would read the game cartridge, but it says “EMPTY.”

Thank you for your time.