This team takes an OUTRAGEOUS amount of threes, it is not unimaginable they go ice cold for 4/7 games and go home.
Yeah it's not at all hard to imagine getting another series like last year's ECF: Celtics go cold, the opponent gets hot, and Tatum and another top playmaker get hurt.
Despite their regular season it will take some luck to get through everything, but champions ALWAYS get lucky at some point. Last year's Nuggest had the 2nd easiest possible draw (8 seed, 4 seed, 7 seed, 8 seed), the 2022 Warriors had an extremely easy trip to through the west (two one man teams in Denver and Dallas, plus Memphis without Ja), the 2021 Bucks were getting handled by the Nets until injuries just buried Brooklyn (and still almost lost on that Durant shot) and then faced a very average Atlanta team, the 2020 Lakers got the 4 month rest midseason (yes everyone got that, but due to their age and injury history they benefited more than most), the 2019 Raptors got the benefit of half of the dynasty Warriors getting hurt in the finals, the 2018 Warriors were down 3-2 in the WCF against Houston before Chris Paul got hurt late in game 5 and missed the last two games, etc etc etc etc.
Luck is indeed the residue of design and the Celtics have put themselves in a great position to capitalize, but it will still take luck. The massive amount of injuries to key players on potential playoff opponents may already be their lucky break.