Why would you expect the COVID "lockdowns" to meaningfully reduce CO2 emissions? There was no concerted effort to reduce emissions or energy consumption, and in fact the opposite happened.
Demand for shipping, including large shipping containers and many small online-order car deliveries, skyrocketed.
People were working from home instead of large office buildings, which means less efficient use of energy in smaller heating and cooling systems
Energy use in homes (for heating, cooking, cooling, and lighting etc) is responsible for about 11% of greenhouse gas emissions.
Energy use in commercial buildings about 7%.
On the other hand, fossil fuels being directly vented into the atmosphere (from leaks, or burning excess fuel) also contributes 7%.
Agriculture, mostly meat and dairy production, and deforestation driven by producing feed for livestock, is responsible for about 18% of greenhouse emissions.
Reducing emissions is really straightforward, and no mystery. It hardly needs new technology, just better deployment of the technologies we already have.
Coal produces about a quarter of total energy, but nearly HALF of all emissions. We need to stop burning coal YESTERDAY.
We only generate about 10% of total energy using low-carbon sources like nuclear and renewable energy. We need to scale those up.
In addition, we need to replace inefficient energy use with more efficient energy use.
Lighting accounts for roughly 5% of all energy consumption. With incandescent lighting being 5x to 10x less efficient than LEDs, we can save about 1% of global emissions just by switching all the remaining incandescent light bulbs.