Your DJI can't cope with doors. 100g of explosives don't do much, see Ukraine where this was attempted multiple times with very limited effect. And most importantly, your DJI enjoys massive subsidy because it is mass produced for entertainment, any custom weapon system would be at least an order of magnitude more expensive. This is already the case in Ukraine btw, with FPVs being comparable in total cost to entry point Mavics, despite being MUCH cruder.

It's not a winning proposition when you take into account that those FPV launches require teams of dozens of people to support, and that good old artillery is both cheaper, scarier (=more suppressive), and more effective.

Launch 100,000 drones against what target? How do you find the target? How do you get to it without getting detected and destroyed? Where do you launch from, what's your launch platform, and is it survivable (if you just plan to bring trucks to the front line, they'll just get blown up pre launch)? How do you deal with high power directed microwave, lasers, or just basic AA shells filling the air with shrapnel for peanuts? How do you coordinate the attack, especially under EW, without saturating all bandwidth available way before you reach 100,000?

You're severely underestimating the challenges and how much it costs to solve them. There are multiple reasons why torpedo boats never worked against competent navies, despite being theoretically much cheaper than battleships or modern destroyers; many of those reasons still apply to those ideas about cheap drones.

In the end it might very much be cheaper and more effective to use a good old JASSM-ER.