keep most BTC in cold storage and only a small amount in a hot wallet for regular use.
I have nothing to say here. Except that I do not use Bitcoin for regular purchases, so a large chunk is kept in cold storage.
And for trading purposes, I have two wallets that are open source. Normally fetch from there to fill my trading wallet.
I think that people should know that too much of everything is bad, a good security also depends on how easy and simple your setup is for you to manage. It's a good thing that you're trying not to put or expose your coins, but when the layers of separation is too much it can actually complicate things and you might even end up forgetting things.
Bitcoin security is no longer difficult to understand if you can read and write. If you can't read or write, don't bother going into Bitcoin because there will be a vulnerability in the security, as you will need a third party to help in that matter.