at current difficulty, one solo miner ( like a bitaxe) would take thousands of years to find one block. youd never make it to a new difficulty adjustment ( every 2016 blocks) and the network would effectively be dead, ya? no more blocks would be found.

The difficulty adjustment is every 2016 blocks or approximately 14 days

One miner would have no competition.

Depends on hash rate and price and difficulty

I am going to ask a telegram group