It shouldn't be insufficient material. I think they have an engine background, if black is winning he should win after white timeouts, but I am not sure.
Would that mean that if Black still has mating material (maybe a queen, rook, two bishops, four pawns) while White has more material (queen, two rooks, knight, two bishops, five pawns) and White's position is safe then White flagging would NOT be a win for Black because the engine would identify White as better?
The US Chess rule is that mating material is any or all of: <1> at least one queen; <2> at least one rook; <3> at least one pawn; <4> at least two bishops that between them can travel to any square on the board; <5> at least both a bishop and a knight; <6> at least three knights; <7> two knights when the opponent has a pawn; <8> either one bishop or one knight with no other non-king pieces if and only if there is a forced mate with those pieces.
FIDE says that mating material is anything that could result in a mate if both players cooperated (a lone knight is mating material regardless of the size of the opponent's army if the opponent has at least one of: pawn; bishop; knight; rook) (a lone bishop is the same except that rook is removed from the list and the opponent's bishop has to be one that travels on the opposite color squares as the player's own bishop).
Accept the loss like a grown adult, you don't gain in the long run by planning to cower out of inevitable defeat. This is a bad attitude to have in life, no matter how bad you are.