External firmware flashing on new device

NOTE: I put an arbitrary price because I know it may be a simple project for most, and the device used could be very cheap. So as far as budget goes, for the sake of openness I will not put a ceiling or floor on my budget. Greetings, this is a little bit out. Of the scope of what’s usually asked for. I am an it tech- mostly repairs, web design and networking. Lokewose I have my tia A+ and networking + ceros as well as my ceh 10. I am researching nag modern uefi vulnerability because I have witnessed cases of things happening that absolutely should not happen. I have 11 months of analytics, tested hypothesis, and note summaries of all interpretations, deductions and conclusions that started with a null hypothesis. Unfortunately I am not an expert microcontroller programmer at this time. I can do the basic projects, but flashing breached uefi’s is above the pay grade to multiple ‘speed racer dilemmas. —- So, as to make a definitive conclusion I searching heavily to invest in a pc /motherboard. That Has the uefi lockeD. This could be old, new, cheap, used, expensive, etc. but it’s important to my research which of your like to hear more about is gladly fill you in. But again For my project I am looking for a motherboard or device that has the firmware LOCKED, and this cannot be altered in anyway.