No armor will ever lower your stats. However every armor has a derived statistic called armor penalty which decreases your movement points, dodge, evasion and stealth by the same percentage. It's capped at 95% (can be lowered with feats) so if you plan a heavy armor character with armor penalty at, or near that cap you should dump agility and all skills based on it, as they will become (nearly) useless.
There is one exeption to this. 6 agility for characters with 95% armor penalty who need to take sprint feat as the only way to gain mobility, for example heavy sledgehammer users with heavyweight feat. They should still disregard agility skills as mentioned above. Tabi boots also give flat movement points which are unaffected by armor penalty. This is actually a bug because those MP should decrease as from any other source. I think a fix is planned for the next patch.
If you have at least 6 int, in most cases it pays off to invest in armor sloping and nimble feats to significally lower the armor penalty. It's possible to make a super steel armor brawler with capped 95% armor resistance and still low enough armor penalty to be able to use lightning punches feat, hoever not until later in the game where you not only need good quality super steel plates but also high enough crafting skills. Junkyard can give you up +2 int poins temporarly which is a great help in this matter.
There is no relation between armor and dexterity.
Thank you for the long answer
I'm gonna make my first character so i want to try out atleast 3 of the craftings skills.
I just have a few offtopic questions hope it's okay
Would you say it's better to have 8 str and use heavy armors or 6 str with riot gear and 5 points in con and conditioning?
I want craft alot and use pistols, smgs, grenades, and AR as offensive so i'm thinking something like this
st 8 or 6
dex 10
ag 3
con 3 or 5
per 8
will 3
int 4
skills:
guns
throw
lockpicking
mechanical
electronics
chemical
biology
tailoring
it's my first character but i still wonder if i have thought out an okay build?