3b. Being proficient with a skill seems to not really matter. For example I created a character who should be very persuasive , yet tends to fail on easy DC persuasion checks (less than 10) however when I try a skill I'm not proficient with that has a harder DC option (higher than 13) I tend to succeed. While it does feel nice succeeding something that you assumed you were going to fail at , it does make choices in character creation seem pointless.
Your experience with rolls are anecdotal, but also just the nature of early level skill checks. You are a level 1 adventurer and your ability to influence the world isn't much greater than a commoner yet. As your character increases in level, both their attributes and proficiency bonus will increase, which will create a more pronounced effect on skill checks.
Your highest possible bonus to a skill check at Lv1 is +5(3(MOD)+2(proficiency)) without assistance from spells or expertise. A level 20 character can have a +11(5(MOD)+6(proficiency) without assistance.
