Good lists of lessons you have posted there. When I was a newbie, I trusted the market too much and did not expect it to drop massively, now just to add, do not believe other people's speculation and never ever indulge on hypes when investing. Have your own decision when it comes to your investment.
This happened to me. I did all the bad things like panic selling, keeping a seed phrase online, losing crypto in crappy exchanges that got hacked, putting everything in a altcoin that had no purpose, and being caught in horrible anxiety. I even ended in the hospital one day, not fun. Back then around 2014 I had another bitcointalk account "itos", sadly it got hacked and made this new account instead. Tried to talk Now I am more disciplined and have learned from mistakes. Hopefully, new people that want to have some of their portfolios in crypto can learn too.
Thankfully the market and blockchain technology is more evolved now and I think at least big exchanges like Kraken and Coinbase are fairly secure. If you are a trader I suppose it makes sense to have some funds on exchanges. Make your own decisions and don't let emotions do the trading.