This two-test series marked an important landmark, as Bangladesh won their first Test against New Zealand in their 16th attempt. The series was drawn 1-1.
Results of all Tests between NZ and BD:

Overall: 17 tests: NZ lead 13-1, 3 draws
In NZ: 11 tests: NZ lead 10-1
In BD: 6 tests: NZ lead 3-0 with 3 draws.
Most runs (minimum 350):

Tamim Iqbal leads with 908, followed by Shakib (763) and newly-retired R Taylor (746).
Highest individual scores (Minimum 110):

TWM Latham’s 252 in the second Test is the highest for NZ against BD, surpassing the 202 by SP Fleming at Chattogram in 2004. Their previous best in NZ was 200* by Williamson at Hamilton in 2019. Also note that Shakib had made 217 at Wellington in 2017.
Incidentally Latham is the first player to score 252 in a Test.
While there is not enough data for meaningful batting averages, we have some strike rates:
Highest strike rates (Min 1000 balls faced, all instances):

Not surprisingly, R Taylor has the highest strike rate. Williamson and Shakib are slightly lower.
Bowling:
Most wickets (Minimum 10):

Vettori (51) is followed by the current trio of Wagner, Boult and Southee.
The most 5wi are 5 by Vettori and 3 by Wagner.
The only 10wm is by Vettori.
Best innings bowling (including all 6wi):

Shakib has BD’s best innings figure of 7-36 at Chattogram in 2008. In this series, Ebadot took 6-46 which is BD’s best innings figure in NZ. The previous best for BD in NZ was 5-166 by Rubel Hossain at Hamilton in 2010.
Best match bowling (7wm and above):

Vettori’s 12-170 at Chattogram is the best performance here.
Ebadot’s 7-121 is BD’s best match figure in NZ. The previous record was 5-88 by Mashraf Mortaza at Dunedin in 2008.
There is not enough data for meaningful bowling averages etc, as Vettori is the only one with over 2000 balls bowled.
Fielding:
Most dismissals (Minimum 8):

McCullum (28) and Watling (26) have the most dismissals.
Watling (26) and McCullum (24) have the most catches by a keeper.
Mc Cullum (4) has the most stumpings.
R Taylor (17) and Sinclair (12) have the most dismissals by a fielder.
Most innings dismissals (Minimum 4):

Imrul Kayes has the most catches by a keeper in an innings (5)
During this series Shadman Islam and TWM Latham both took 4 catches as fielders.
Most match dismissals (Minimum 5):

Watling (7) has the most dismissals by a keeper in an innings (all caught). Next is McCullum with 6.
The most catches by a fielder is 6 by Latham in this series. Next are Sinclair and Shadman with 5.
All-round performance:
50+ and 5wi in a match:

Vettori’s 55*, 76 and 9-133 at Chattogram in 2008 is clearly the best. If he had taken one more wicket, he would have become one of the only five players to score 100 runs and take 10 wickets in a test (The others are Davidson, Botham, Imran and Shakib).