The upcoming Halving Bitcoin will double the cost of mining, causing the price to skyrocket to $ 90,000 or higher
if your employee cuts your paycheck in half, you cost (like your electric bill, your rent,...) doesn't double. your "income" is cut by half. the same is true about bitcoin block reward halving.
For operators who use high-speed computers to mine BTC,
what the hell is a high-speed computer

you mine with ASICs not computers.
The estimated average cost to mine a Bitcoin could rise to $ 12,525
wrong for the same reason as above.
double the current average of $ 6,851.
this number is also pure nonsense.
mining is not a fixed thing to have a fixed cost. the cost depends on each and every single miner. for instance if you mine bitcoin in Hawaii (29.18 cents) your cost is obviously a lot higher than someone who is mining with electricity that costs 1 cent.
Basically, miners will have to run twice as many calculations,
wrong. what you refer to as "calculations" depends ONLY on difficulty and that does NOT change with halving.