blockchain – Why run a riskier light node and be subject to more fraud than a complete node? We do not need a complete accounting book, right?

I have been reading in the light node and many have pointed out that the light node does not have the complete blockchain and is more risky because they can not verify transactions completely.

First, we can verify or validate the transaction on the website. I do not understand why we need a complete block chain if we are not mining.

Second, does not the miner verify the transactions before including them in the block? Besides that, did the validation process of the block serve as a double validation?

Third, when the block is added to the network, is not it a third validation?

Go ahead, when the block has several more confirmations, is not that a fourth validation?

In this case, why do we need a complete book? After a certain amount of time, many of the previous blocks seem redundant.

A light node, although it does not have the complete ledger from the genesis block, keeps a section of the most recent blocks, is not that enough?

Why would a light node be riskier? Realistically, what are the possibilities of receiving incomplete or invalid blocks?