I certainly got the impression that there was some internal fire visible in the engine bay shots of Ship's ascent, I wonder if that was significant?
However speculation by mere mortals like us on the causes of the failures is utterly pointless, how could we possibly guess?
Re the repeated failures, I'm reminded of Colin Chapman's radical approach to Formula One design in the 1960s which went along the lines of keep lightening it until it breaks, then beef it up a bit until it doesn't. He got there in the end and wiped the floor with the opposition. It cost a lot in breakages - including broken drivers in his case, but it worked well. Spacex have a similar mindset.
The technique is vastly quicker than traditional methods of development even if costly in hardware and combined with their brilliant innovative approach to design is making huge advances at a tremendous pace. Bear in mind that we (globally) all fund this indirectly by using Paypal, Twitter, Starlink and buying Swasticars etc. They laughed at and criticised Stevenson, Brunel and the Wright brothers in their time too...