As an an example:
Anyone can connect their wallet to my node.
If you are running Bitcoin Core, then it is your wallet. No one else who is running Bitcoin Core needs to connect to another specific node, since they are running their own. (But of course their node will connect to other nodes as part of the normal bitcoin network.)
If you are using a closed source wallet such as Coinomi or Trust, then that wallet probably exclusively uses the servers of the company or entity which built that wallet, and the users can't change that. Such wallets provide no privacy and very poor security, but for some reason people continue to use these wallets.
If you are using an open source wallet such as Electrum or Sparrow, then yes, those wallets will connect to public nodes/servers in order to obtain the necessary blockchain data. You could host your own public Electrum server with your node as a back end for it, if you so choose, which other people could then connect to with their Electrum software.
Thanks for the detailed answer
I was going to use Electrum and create a server with "electrum personal server"
and I would then connect the server to my node, which only connects to other nodes via tor.
But how exactly do these people find my public Electrum server?
Does it automatically appear somewhere?
And what would be the pros and cons of making my node accessible to everyone?