I’m not up on Russian armor, but historically the weak points of tanks have been the rear ends which covered the engine compartment or fuel load. A thermite grenade is essentially a canister, like a soup can. Put some adhesive on the bottom of the grenade so it sticks to whatever it drops on, wire the grenade to the drone so when it drops the pin is pulled. Thermite burns at about 4,000 degrees, more than sufficient to melt through all but the thickest armor. Mostly agree with your points, but that’s the beauty of brainstorming. Ideas pop up. Some of the most effective tactics in previous wars were achieved by “out of the box” thinking. For instance, during WWI a Canadian unit was attacked with gas. A doctor saw the gas cloud coming and suggested that the Canadian soldiers urinate on some cloth and hold it over their faces. The urea in the urine reacted with the chlorine and mostly neutralized the deadly gas, allowing the Canadians to hold their positions and thwart the German attack.
As a side note I think last time thermite was considered an anti-armor solution was early in WWII and it proved inefficient enough to get outclassed by regular anti-tank shaped charge cumulative grenades. Thermite doesn’t burn through armor good enough in practice, let alone there are decent active anti-fire equipment stuffed in modern tanks to negotiate this threat.
In reality, there are no compact ordnance effective against MBTs left.
These are mostly absolete since 1970s. Not only hand grenages, but LAW, RPG. Modern anti-tank weapons are barely man portable.