Edit: So the exact formula was datamined. The way it works is as such:
1-50 gives a bonus point for every 5 as per below
50-150 gives a bonus point every 4
150-300 gives one every 3
300-500 gives one every 2
and finally 500+ gives 2 per point spent.
Another repost of my work that was already posted on reddit but I kept seeing people asking about:
So
everyone should know by now that you get 1 stat point per level (not
including level 1 however) and 1 stat point per statue you’ve touched
(and maybe from some quests according to some sources)
However 1 stat point spent does NOT equal one stat point gained. You
actually get more at set points it starts every 5 stat points you have
in a stat including the base ones for your class. After 50 total points
invested you’ll have 60 points in the stat. Then it switches over to
every 4th point until at least 91.
here’s a spreadsheet with all the bonuses marked, and some projected bonuses that are untested at the bottom.
EDIT
too many people are confused so here’s some examples
So for example if you have 9 con starting as a swordsman and you add
2, your con goes 10, 12 cause 5-6 added +1 bonus already which is
included in the “9” you see on your sheet and 9-10 added +2 bonus so you
see “12”
same swordsman starts with 8 and would add 3 to str to get 9, 10, 12.
dex starting at 6 would go 7,8,9,10,12,13,14,15,16,18 cause at 15 you get your 3rd free point making it 15+3=18