The Heat really, really need game 3 Bam in this series and that just hasn't happened. No question TL and the Celtics matchups are a part of that---they have three guys who make it hard for him and present different challenges (with Grant he can shoot over him; that doesn't work at all against TL, and largely not against Al. Against TL he can try bullyball, but he isn't strong enough to do that with Grant or Al).
What Miami tried to do with Bam in 4th quarter, having him start the offense and drive/play into the paint, probably is a place to focus more in game 6. But this is where the lack of 3pt success matters, Bam isn't a top-tier finisher and the Celtics are sagging to clog the lanes when he tries that. Bam is a good enough passer to turn that into looks, but they aren't hitting enough of them. And Bam hsan't shown, energy-wise, he can be the offensive focal point for 50% of the offensive possession that a Butler can.
If I were guessing, Heat's big adjustments will be:
1. Sit Lowry, benching for Vincent and possibly all the way out of the game (or trying to get him down to 15ish targeted minutes). He just can't compete at the level they need him.
2. Try more Bam as point guard to create earlier looks for him and also to force Celts to open up the paint a bit as they match up wtih Bam above the foul line (as they don't want him to get a head of steam---they aren't worried about his jumper up there)
3. Play Herro in whatever shape he is in early, to see what you have. Him being even somewhat a threat offensively would help a lot. And if you learn he just can't contribute, move on to below
4. Try some targeted pressing/traps to generate turnovers, especially when Smart or Al is off the court. Miami will need to go deeper into the bench to do a lot of this---they are lacking in healthy bodies. But they need to try; Vincent, Oladipo, Martin, Butler, Bam is a decent press unit, sneaking in a shooter at times (with more half-court trapping if Robinson or Strus are in there)
5. Keep trying to get Strus and Robinson free and hot. It may well continue not to happen, but they cannot win if they don't get more offense. I know I was the outlier a couple games ago arguing their offensive need was bigger than their defensive one but I still believe that to be true and those two are among the only ways they might improve. Robinson/Strus haven't answered the bell often (and Strus may be hurt).
6. Experiment with Butler posting up. There's tons of reasons this may fail---it's not his core game, if TL is lurking it's a problem, and he may not have the power with broken wheel. But he's a great finisher and they have not been able to get him to be effective on-ball since the injury and they need to generate points. Bam up top as high-post center and Butler down low might generate some offense and will invert Celts preferred back line defense. Though bam's lack of a jumper limits how well you can leverage this