[Ethereum] Does Gas Limit have any bearing on transaction/mining time

The gas limit should be as high as your transaction will consume, and no higher. The amount of gas a transaction consumes depends on what it does. (Bear in mind that if your transaction results in gas refunds, for example because it deletes storage data, you still need to account for it in the gas you supply.)

Most miners will fill blocks up to the limit, and it's OK to set a limit that takes close to or all the gas available in a block, but since miners take transactions with higher fees first, this will increase the gas level you will need to set to outbid other transactions that could fit in the block. So you will need to compensate for the higher gas limit by setting a higher gas price. See https://ethgasstation.info/ for specific data on how high a gas price you are likely to need for any given gas limit.

If you're just doing a simple send, just use 21,000.

As I know, it places an upper limit on the gas limit of transactions Gas Limit in a block, therefore a validator cannot extract a quantity of transactions whose summed limit gas will exceed the gas limit value, am i right ?

The block gas limit is more of an upper bound on the total gas used by all transactions. See this piece of code from the Ethereum consensus :

// Verify that the gasUsed is <= gasLimit
if header.GasUsed > header.GasLimit {
    return fmt.Errorf("invalid gasUsed: have %d, gasLimit %d", header.GasUsed, header.GasLimit)
}

So seems that it is not really related to the block GasLimit field. So there is any relation between the transactions gas limit and the block gas limit ?

There is one, a tx gas limit cannot exceed the block gas limit, as you can see here.

So the sum of all tx gas limit can be above the block gas limit, but the sum of all tx gas used cannot be above the block gas limit in the same sense that a tx gas used cannot be higher than its own gas limit.

I hope that answers your question.