Does 6 months old=terrible 2's

God, little kasper now big kasper has been growing and getting big, now he's about 20kgs but he has taken 2 steps back. He has been getting better with his recall off the lead and general behaviour when out but still a bit rambunctious with selective hearing and always playful with other dogs he doesn't even know what aggression is I think. But as the weather has gotten wetter than usual (merry old england) and we've been letting him and jess spend more time in the house during the day and not only the evenings, he's decided that if we put them out for pee time or to settle at night in the kitchen he will chew the door frames and doors. He's not one for toys, if we give him a toy he'll play for a while no matter how exciting we make it for him then gives up, but he'll gladly take things he cant have like dustpan and broom, mops shoes etc. as the best toys on the planet.
Is he still just testing boundaries because he knows he shouldn't do it by his reaction when we enter the room and discover bad doings he cowers waiting for the telling off but we don't want him to become timid because he is misbehaving more often now than when he was younger.
Any advice please?

Six months is meant to be the start of the teenage phase. Basically, he starts doing things he's meant to know is wrong. It'll probably be a stressful nightmare, but just keep training him as you did when you first got him and eventually it'll pass

when does it pass? (seriously, I'm not trying to be funny)

That's about the age it starts. Go back to basics and it will pass in time

ARGHHH, SOB, now he's started to realise he can * his leg and pee and seems to be back to doing it in the house, we thought he was trained by now as no accidents even over night. But now he has a new trick, cocking his leg no more scooting down as a bitch does and is doing it for the sake of it or so it seems.
Things were going so well until i told the missus he wouldn't do it as now he's trained then BOOM. As I said before ARGHHH.

Think rebellious teenager with raging hormones and uncontrollable drive to test the boundaries and make his mark (pun intending). It does pass. Just go back to basics, be consistent and take some chill pills. It will all be over in about 18 months