I can’t remember the last time my Mini-14 failed. Mines an older one so not sure what the quality is like on the newer ones
If you had so many malfunctions - you should look first at the ammo you use.. the mini 14 is a VERY reliable gun..it’s a semi auto - ammo choice is the main factor to make it run well. Did you clean it and lube it before using it ?
Years ago I had bought several Stainless 581 series Minis from Frontier firearms. They went for the rather low price of $650++. All the guns I received were extremely overgassed and would often cycle so fast that the bolt would come back while the casing was still obturated and would either pull the extractor over the rim or tear the rim right off. I would suggest inspecting your cases to see if something similar is happening.
The Mini gas system has a little bushing in it. Clamped between the barrel and gas block, guarantees positive alignment, and its internal diameter is in effect the actual gas port. I wonder if it could be replaced with one with a smaller hole, if, in fact, too much gas was acting on the slide.
Warranty