As others have said, close detail photos of the cutters on your chain will help- but there is absolutely NO SHAME in not getting the perfect file until you learn the technique that suits you and the timber you are cutting- absolutely 100% none of us were experts in the beginning and if like me you cut a lot of softwoods- you can get away with murder damn near in the filing and still do okay, hardwoods are more demanding.
As for a bigger saw and bigger bar- I would drop any ideas of the MS270 like last months milk. The 51, maybe- but you could do a lot better.
I would be looking at 60cc saws or better. Something like a 262, 266 (365)Husqvarna- or 034, 036 (MS340-360) Stihl.