Ethereum Nodes?

This is probably a noob question. I am just trying to understand, I am dumb and please tell me if I am posting in the wrong sub or breaking any community rules? Thank you in Advance!

I often hear on CT that some of the people are running a bitcoin node at home and it is important for the node be designed in such a way that anybody should be able to run a bitcoin node at home despite limited resources and little technical knowledge for a network to be decentralised. And Nodes play an important role in Bitcoin network by enforcing the rules, so this part of node network must be independent from the Miners to stay decentralised/to avoid collusion(?).

Now my question is, how is this being done with Ethereum now for example? I am not asking about the staking part (which is equivalent to mining of bitcoin) but the enforcing rules part? Are there ethereum nodes that exist just to propagate the news that a block has been discovered as per the rules? The nodes that are not Validators? Considering validators need 32 ETH for staking?

And are these nodes in Ethereum network equally easy to build and run independently like the bitcoin nodes? Because I see everybody writing on CT that they are running bitcoin nodes proudly and I see Ethereum users writing about running validators (with 32 ETH) but not the ethereum nodes?

And finally how has the other good projects like Polkadot solving this? Are people independently running DOT nodes at home? I guess not, right?