The data sources used to inspire this proposal is as poorly thought out as this idea. I'll focus on your citations as @ABCbits has already showed the gaping technical issues with your proposal through his questions.

The first citation you list, The hidden environmental costs of cryptocurrency (found at https://collections.unu.edu/eserv/UNU:9528/UN-IWEH_BTC_Report.pdf), uses information from your second citation, CBECI.

The first report even notes this and helpfully summarizes the methods used by the CBECI:

"First, the monthly electricity use for BTC mining in the 76 BTC mining nations monitored by CBECI between January 2020 to December 2021 was roughly estimated using the average monthly hashrate share of each country and the total monthly electricity use of the global BTC mining network. Then the average carbon, water, and land footprint of electricity generation in each BTC mining nation were estimated [41, 42] based on its energy supply mix data as reported by the International Energy Agency (IEA) and the environmental footprints of electricity generation from different sources using the scientific literature data on footprint valuesy [41, 42]. Multiplying the BTC electricity use in each country by its footprint values provided the carbon, water, and land footprint estimated of BTC mining for that country."

So even if all Bitcoin miners switched to using renewable energy today, the data collection method would still hold them responsible for the carbon footprint of their residing countries. For all we know this could already be the case, but the data isn't able to tell us.

It's almost academically dishonest to reference those numbers in any serious publication. The CBECI explicitly mentions these assumptions (https://ccaf.io/cbnsi/cbeci/ghg/methodology), so they can argue they don't hide it, but publishing this information with such uncertain methods in the first place should be condemned.