As far as the 3 betting question, yes this is good although you probably went a little larger than normal but it is important to know for 3 bet sizing if you are going to make an error (not saying your play was an error) make the error betting too large vs min 3 betting which I see too much of.
As far as the hand is played out, when villain donk leads I am thinking that I am going against Ax here that was too afraid that I would check behind if it was checked to me with the board having two spades. This is a micro tourney so you never know what villain is thinking (if thinking at all) but I would personally think I am behind and would consider folding here. In game I probably call and then fold turn but realistically if I am thinking I am beat on the flop I should fold. Not sure what you exactly thought of this donk bet but it seems a weird place to bluff. Some in the micros will lead here with 8x but not sure how many 8xs villain has that pre flop raised and then called a hefty 3 bet. I believe their range is Ace heavy here and folding is probably the best play.
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