Bringing back decorous behaviour

The following happens very often :
dead drawn position
A proposes draw
B blunders (the psychological pressure, trying to force the win etc...)

Draw proposal should no longer be valid.

Another variation :
A plays a much stronger opponent and proposes draw in total fairness after an equal line opening
B blunders many moves after (gives the queen on move 30, misses a mate in 1 threat etc...)

B just has to call draw before A moves.

I still believe 3 proposal per game is fair.

In either situation, player A must manually withdraw their proposal (if using "two-phase commit" implementation).

The following happens very often:
A proposes draw
B moves before seeing the draw offer
B proposes draw
A moves before seeing the draw offer
A proposes draw
B moves before seeing the draw offer

especially in time trouble. The draw button is worse than useless in such a situation since it almost never works and it distracts both players.

Yes, draw offers should be withdrawed manually.

No, as in competition, you propose draw on your move and the opp accepts or plays along.

No, it's not. You propose a draw on your move in time struggle, and your opponent moves before seeing the draw offer, so it's cancelled.