I dont know if this poll needs any wider explanation, the shallow ships BR seems ok considering there aint any carronade meta, it feels evenly balanced (if you're close carronades are obviously the best, but atleast cannons have a chance).
Now speaking about the lineships (4th and up) this game strives for being hardcore, realistic, and beautifully detailed naval combat sandbox so when 0.05% of the lineships posted beneath are the ships that was supposed to be the "backbone" of the navies durying 18th century it gives a wrong picture of how the combat actually was.
Considering the reason 3rd rates were the "Meta" during the age of sail was due to the lack of timber which we ingame have more or less an unlimited amount of and would probably never change, the best bet would be to adapt the BR to force the fleets to not prefer to bring 2nd and 1st rates unless its like the very last outcome and people arent available for the port battle.
BR Proposal
Current:
st rates
800>
nd rates
540 - 600
rd rates
400 - 550
th rates
<340
New:
st rates
1500 - 1800
nd rates
900 - 1000
rd rates
450 - 750
th rates
<400