I suspect to really answer the question we need to compare this with other teams. Ideally we also want to look at the % of shots we take that are Very Tight (0-2 feet from closest defender), Tight (2-4 ft), Open (4-6ft) and Wide Open (6+). You can get the data from NBA.com, rather than posting the screenshots I will just post the query I used, changing the filter to the different categories:
https://www.nba.com/stats/teams/shots-closest-defender/?sort=FG3_PCT&dir=1Celtics:
Very Tight (0-2ft) - 0.1% of total shots, 33% success rate (14th)
Tight (2-4ft) - 5.2% of total shots (1.3 from 4.6), 28.2% success rate (16th)
Open (4-6ft) - 18.1% of total shots (5.4 from 15.9), 34.1% success rate (16th)
Wide Open (6+) - 18.3% of total shots (5.8 from 16), 36% success rate (25th)
I will post the screenshot of that last one but you can get it yourself from the query I built:

Sorry for how tiny the text is, its the only way I could fit the Celtics in since they are 25th.
So given we are 16th and 25th in open shots (to combine the 2 categories would require adding them up together manually so I won't do it for now) it's fair to say we are not one of the league's better 3fg shooting teams. In fact we're probably one of the worst, if we can't even hit wide open shots as a team.
That said, we have been winning despite our mediocre 3fg shooting, why? I'm sure it drives everyone crazy to see our team of clankers letting it fly and building brick houses every game, but the flip side to it is that our defense has gone to another level in 2022. I did these splits this for another thread, you can see how even if our 3fg is mediocre, those we have been playing have been worse on average:

So we don't necessarily have to be a great 3 point shooting team to win
as long as we can maintain our defensive connectedness that has been evident throughout 2022. The caveat - the teams we've been playing recently have been either hurt or bad. But if we're going to apply that caveat to them, we should also apply that caveat to us back in Nov and Dec when everyone wanted to blow up the team when we were losing and building bricks.
There's another stat I've been tracking which is the # of games we have won where we shot less than .300. Over the season's 59 games we have shot below .300 17 times, and only won 6 times...but 3 of those 6 were in the last 10 days - because the other team shot even worse. Whether that's our doing, theirs, or a combination of both, we need to dig deeper. But the data suggests that as long as we continue to defend well and be connected and give the other team bad shot opportunities we will be in the thick of things come playoff time, even if we miss our 3s.
