Bitcoin mining is done by high-powered computers. Which solves complex computational math problems.The matter is so complicated that people cannot solve it by hand.As I write this, the responses of 1 computer to solve this problem are working more than 6 trillion times.
The days when you can use a normal computer to find bitcoin blocks were away too far. ASICs are the machines bitcoin miners use to find bitcoin blocks recent years and they have to join mining pools as it is unrealistic to find a block with a singe ASIC rig.
First, when computers solve these complex math problems on the bitcoin network, they create new bitcoins. Such as extracting gold from mines. Similarly, new bitcoins are created through bitcoin mining.
It is not accurate. Bitcoin miners or rigs don't create bitcoin. Bitcoin is created per Bitcoin protocol and block rewards. When a miner or a mining pool find a bitcoin block, a block reward will be awarded to that miner or that mining pool. If it is a mining pool, then the pool will distribute block rewards to participated miners in that pool.
Second, computers are trusted and secure by verifying transaction information on the Bitcoin payment network.
You said oppositely with the truth. The bitcoin network was secured by more hashrates and more decentralization of hashrates, bitcoin miners and full nodes. Each full nodes store full data of bitcoin public ledger on their device. They will verify data from other connected nodes and help to detect nodes from forked chains if occur.