Yeaha, clean up and oil will do wonders. The symptoms you descibe sound like it is just in need of cleaning
The thread gatherin is a tension issue probably. If you are not in the 3-5 of the tension dial go there first
Then if your bobbin case comes out you can adjust the tension there too, usually it's a tiny little screw holding a thin piee of metal that controls the tension. I regularly check this on my 1960 Husquy
If the needles are breaking check to see that you are using the right foot. My Janome says to use certain feet for certain stitches and if I don't the needle rams into the foot.
Otherwise it could just be the tension pulling the needle out of alignment. And other things may be out of alignment too.
I recently took my Janome apart and fixed a feed gear issue. It still could do with a little more fixing (I think I need to tighten a screw a bit more than I have been able to as well as get all the dusty fibres out). Being from the 1980s it is mainly metal and is mechanical rather than a mix of electronic and mechanical parts. It means it is possible to fix at home
I do have a brand new Babylock though and I'm very happy with it. So I'd suggest fix the work horse and then see if you have need of any fancy serging/sticthing and get a lighter machine for that work. My Husquy is for all historic and leather work. The Janome is for modern fabrics and especially stretch fabrics. The Baby lock does all my pretty hemming and my industrial overlocker is for speedy heavy duty work
And I have an Elna lotus just 'cause it is so cute! Well it does work I just need a new needle screw.