Sorry to hear of issue.... also did not read all of the posts.
Sharpening chainsaw chains is art... not all people can .... I have been cutting firewood and fixing chainsaws since the early 1970. Old now and a full day of chainsaw will wipe me out. I have tried a few times to sharpen chain, just not happy with results... I have 2 small saws, 2 med saws, and 1 big saw. Have not used big one in years. Have 12 saws to fix and sell to others.....
I buy 3-4 chains for the saw... semi chisel non safety chains for me. The drive sprocket will wear out with about 4-5 chains due to getting a groove. Once there is a grove in drive sprocket the chain can get loose and tight and it rides in & out of the drive sprocket grove. With a few extra chains you can bring a dull chain to the local stihl dealer and ask them to sharpen $7-8 and if you bring in a few maybe little less. The chain will get "ground up" faster but the cut is way better. Good Chain will give you chips..... saw dust will not cut, you will over work the saw and could over heat the saw and score the cylinder and piston.
Keep the chain out of the dirt and rocks.... small hit will dull saw by about 25%, hit again and down 50-60%.... If you wood is on the ground.... put a hunk of wood under so off the ground and a "cantileaver" supported longer log or tree limb on the downed tree already will cut up much better. If you wood is covered in mud will dull your chain pretty quick too.
Chain Sharpen is the only part of maint and repair..... I am not pleased with my own work. I also purchased Harbor Freight bench top sharpener....... did not work as well as I would like.... Like new and would like to sell it. You can buy a professional level bench top sharpener if the dealer or town is long way away... but it is a few buck.
Again.... 3rd page was saying I am getting saw dust out of my saw on dry oak trees.
Buy a few new chains and have them on hand..... I gave up on hand sharpen chains....... 30 years ago
Also if the shop shapens you chain and the top of cutter is all blue.... they ground off too much metal and over heated the cutter. Most sthil dealers would replace the chain at this point.