Just looking for custom tips in the best place of the internet

Hi everyone,
I have a puppy, shocking, I think we have been lucky with her. she is only mildly damaging in property and pretty relaxed and well behaved mostly.
She is a pomerian-husky cross. she is more to the small side of the breed. (6 months in and 7 kg)
She is overconfident with almost everything except kids.
very social we got her at 8 weeks and have been doing socialising and dog school from week 9.

Here is were you come in.
my few complaints and also what i do wrong. please give me your tips for these:

1. She is not great at leash walking because i dont train it enough with her because she is not good at leash walking
2. the past 2 months it has been improving really well at dog school. On the walks at home with candy it goes wel but that means 15 min of giving her candy every 3-4 steps. when she gets "fuller" she will need it faster or she will get it and run of. by the end of the walk she just wants to sprint home.
3. she wasnt destructive before but the last week she has been more "bored"? so she is starting to try and eat stuff out of the christmas tree… ofcourse i see it in time but before she could be entertained by the cars pasing through the window for an hour or two. now misschief is there instead. she is a bit moree destructive when bored. but mostly we do 3 stimulating puzzles a day, go for a walk towards the evening, play in between (when i have work breaks)
4. 2 times a week she has been home alone for 5 hours as we both have to go into the office on those days so we do half a day. those hours were fine, untill this week apparently. now she is becoming more destructive/bored? I was so happy she could be out of the crate when we left 2 months ago, now i'm wondering if she should be crated back for those 5 hours or if we should make the room she is in smaller (so she cant reach the christmas tree and presents). should i leave more stuff out, i always leave her with a puzzle or something to occupy her a bit.
5. Any tips?
6. We are closing off our garden for her so she can run freely (not leashed) outside as it feels like she needs to have some zoomie time (we now just run back and forth in the living room, parkour!)
7. She loves the cold and at friends places she will be in their garder for hours. I am afraid of her being stolen though. how do you schedule, protect your dog when they are playing and runing out in the garden.

Thank you for going through my whole text! For how stubborn the breed is and high energy , she is doing so well, i love her so much !
What did you do that worked well?