The way to cripple a company is to get bad people promoted into management and have them optimise something plausible but not profitable. Like what happened in a lot of slow-fail engineering companies - insist on maximising the profit metric to the point where the actual product becomes compromised. That strategy can be intiated from almost anywhere in management too because a constant "what if we optimise for profit" [1] usually does well at meetings.
Being a destructive CTO is almost too easy. Just don't do anything much, weed out any competent people in the level below you and develop a culture of pushing blame aaaaalllllllll the way down the org chart, ideally out of the technical part of the tree, so that nothing broken gets fixed. When people catch on, allow blame to move 1 level up the org chart and do a big shakeup to clear out any institutional knowledge that might have built up in spite of you. That game can go on for years.
[0] I've seen people where "do things through official channels" and "demand written orders" would have made them more productive. We are our own worst enemies.
[1] Yes, the irony here is that naive optimising for profit is typically not profitable.