A few things I have observed over the years you might want to check. Take a flashlight or something and look at the actual contacts in the port and see if they are bent. Sometimes the old cheap 4 in one carts have poorly made PCBs what arent beveled correctly or are too thick and squish the pins and they no longer make good contact. It looks like an official one in the pic but unless you have had this since new who knows what someone threw in here. see here for some more info on that

Also these backup carts do just sometimes go bad though I don't know if I have ever seen an official one go bad but buying a new one to test may help with that as they aren't that expensive. They also usually have lots of built in features like an action replay and acting as an extended ram cart. Just make sure to try and check that the pcb is made correctly with that link above

Have you thought about getting a new one? /s

Have you tried cleaning the memory card and port with isopropyl alcohol?

New OS what do you mean? My SS has a fenrir and a working memory card slot and I still find it a pita dealing with saves on this console. Luckily batsugun doesn't really need all that much save wise.

Possibly the cartridge and not the Saturn?

Have you tried turning it off and on again?

Sorry, I had to double take when I saw the crystal left of your center speaker. I thought I was trapped in another “find the dildo” moment.