Let’s see if I can help you make some progress.
First, if you got the GND buzz get louder when you touched the strings, then you are likely to have had a broken GND connection like the video you posted. This could have been from the solder lug breaking.
Second, if you received a second jack with the guitar, then this is a red flag to my engineering mind. If the designers thought they needed to supply a replaceable jack due to breakage, then it is likely to happen more than once, and the part is low quality and a poor design choice you are probably now stuck with. I did a very quick survey of Amazon and did not locate a replacement, so you will need to do some searching, and possibly look at the guitar manufacturer as a viable source for the replacement.
As for the jack, it is a 1/4 inch JACK. Jack means this is the receptacle side of the connection. It is also a “panel mount” which means it is intended to secure to a flat surface with a hole big enough for it to stick through. I’m guessing that it is fairly long and the connection to the plug is enclosed so you cannot see it. I am not sure how it would be captured at the point you plug into it, but I’d think it would flare out and hold against the outside of the guitar, maybe against a metal plate.
I misstated my initial comment, the connections for this should be to a tip and to a sleeve. These are relative to the plug. One thing I am uncertain of is that the image you have shows three lugs. There are two different ways you are likely to have this.
- the connector is designed for stereo, so you have a tip, ring, and sleeve connection lug for left, right, and common (ground usually). I’m unsure of the order for left and right, but the tip is the correct connection to make because you’ll have a tip and sleeve on your instrument cable.
or
- a mono with disconnect jack that is intended to break a connection between two lugs on the jack, which are not the sleeve, when the plug is inserted. This is used for making a default internal connection when nothing is inserted, like on headphones, but then disconnect it when the plug gets inserted.
Since neither of these are needed on a guitar, I am confused by the three solder lugs.
If this were mine, I’d get a good look at how it is inserted in the guitar. I’d take it out and look for a manufacturer I could look up. I’d try to measure the continuity from a cable to identify what lug hooked to what part of my cable (I hope you have a meter like the guy in the video showed). I’d go shopping for a replacement that should fit, or examine the diameter of the opening to see if I could select some different jack (unlikely). In the US, we have a couple respected hobbyist parts vendors. I’d start with them if I didn’t find this at amazon - DigiKey and Jameco come to mind. You may need to look in your country for a similar vendor.
As for “same spec” question, well, there is very little to specify beyond the obvious physical size and shape, but there are things you can look for that relate to quality. In your case here, I don’t think you have much to work with. Just finding a replacement will be the important part, I think. When you go to solder it back in, read through my tutorial and then make sure not to overheat anything.
If you need more help, think about if a picture can help. For instance, I cannot see the whole jack, I cannot see the wire connecting to it that is not white, I cannot make out what the lugs may connect to - may be impossible to guess with everything enclosed, but the angle make certain I cannot tell.
If you are not sure about using a multimeter to check continuity, ask here and I’ll see if I can point you in the right direction.