Your numbered list, yes that's the steps

With the other person's answer, you have a choice when interacting with a block chain.

You run a node that directly sends commands to the blockchain, this one uses up more storage as it downloads the blockchain but it's the one that requires least amount of layers of trust

Or you use a wallet that uses a trusted 3rd party full node. That's why open source is important for these wallets. This is really easy and convenient and in most cases uses open source software and is built on years of community vendors operating in good faith. These lite wallets, they run on practically anything. You manage the keys to your wallet; it's the keys to authorize transactions.

The "heavy lifting" is delegated to another computer. Heavy lifting in quotes because the idea of blockchains is to be decentralized so one pillar idea is that it should be pretty cheap to run a node

Even having a full node, unless you want to mine, it's really just storage and download. If you want to support the network a bit, some upload so others can download block chain history from you too.

It's like how in Linux most users now just trust that the package maintainers for the distributions package manager is delivering legit software when you apt/dnf/etc software from the default sources

If you're not going to run a node yourself, you'll have to accept some level of trust. Also with an open source wallet, you can with certainty point your lite wallet to whatever full node you want, your own or one you trust