Well said,I agree with your point except where you said Exchanges are safe to hold Bitcoin. I believe this is not the first time investors have been warned never to use centralize exchanges to Hold their Bitcoin assets because they can be hacked. Its fine if your using this exchanges to buy Bitcoin but it's not ideal to hodl because of the risks. Rather than Hodl your bitcoin stash with this exchanges where you don't have complete control over your asset,I prefer you start making use of a non custodian wallet to store you Bitcoin. A non custodian wallet is safer and it allows you to have complete control over your asset through your seedphrase.
If the investor has a long-term plan for investment, then I think it will not be safe to use all these accounts at all, but it will be safer to use his software wallet or hardware wallet. For example, I am talking about Kucoin Exchange, initially I thought this exchange was safe, but the activities they are currently doing with the users seem like fraud to me. Looking at their user reports on the Play Store, I can understand this much that they are suspending most of the users' accounts and asking them to fill out a form, when the users give all the information in the form to the support, the support is not accepting them, and in many cases it is seen that the support is not replying to the messages of the users. Now those who had a small amount of money in all these exchange accounts and whose accounts have been suspended may not feel too bad, but imagine the state of mind of those who have a lot of money in their accounts but their accounts have been suspended. So I would say that software wallets are much safer compared to all these exchange accounts.