If you just run a node and don’t connect your wallet to the node, you’re not really doing anything useful.
Theoretically, you’re contributing to Bitcoin’s decentralisation by keeping an extra copy of the blockchain, but Bitcoin is decentralised enough from that perspective.
The reasons to run a node, I’ve explained here, and it involves connecting your wallet to the node.
One tricky problem exists for Electrum users – The Electrum wallet can not communicate directly with Bitcoin Core. It needs Electrum Server which acts as the “middle man”. There are various versions of Electrum Server (Electrum X, Electrs, Electrum Personal Server) each with advantages/disadvantages.
The easiest way is to run a node “package” which comes with Electrum Server (Electrs).
This article explains how to install Electrum Wallet (including how to verify the download), and connect it to Electrs. This is a newer article that contains the same information, but more comprehensive about how to use Electrum.
You can also connect your wallet to Electrs via Tor. Read this to find out more.
This is how to connect Sparrow Bitcoin Wallet to Bitcoin Core directly. Sparrow does not need a server to sit in between it and Bitcoin Core the way Electrum does, although you can choose to connect to Elecrs.
There are a lot of similarities in connecting other wallets to your own node. I may write more guides on various wallets in the future.