Is it true that every block that is discovered, the person that discovered the block will be awarded 12.5 bitcoins? But to discover such a block, somehow the person has to get a SHA256 number that has all 0's for the first 72 bits?

What if somehow, in that 10 minutes, two new blocks are discovered, or likewise, what if a new block took 20 minutes to be discovered?

And it is 10 minutes per block discovered? So in the year 2022, when the number of bitcoin awarded is halved again, to 6.25 bitcoins, does that mean it is still 10 minutes per block, but now the award is 6.25 bitcoins?

Or does the 72 of 0 bits now become 73 of 0 bits?

So is it true that even in year 2140, when all 21 million bitcoins have been rewarded, then new blocks will still come out every 10 miniutes, and good for recording transactions?

It is said that 1 block is 1MB, and each transaction is about 0.25kb, so 1 block = 1MB, is good for 4000 transactions. So in year 2035, or in year 2140, we can still record new transaction at a rate of 4000 transaction per 10 minutes?