For a while now I've wondered how to build the most stable gaming/workstation possible. I'm sick of crashes, stutters, and general un-reliability. However, it's a balancing act between price, performance, and reliability. (for example ECC memory is stable, but more expensive and slower)

Ideas I've had:

• ECC memory
• CSM sku motherboard
• Hugely overkill power supply, or even dual redundant PSUs
• RAID M.2 boot drives
• All air cooled

What do you all think? If you were to spec out a (realistic) ultra-reliable PC what parts would you use and why?

P.S. I'm looking less for specific recommendations as I am for general ideas, which is why I didn't specify the use case or budget. I'm more interested in the concept and if it's feasible.