The US holds the largest Bitcoin reserve at $12.16B, mainly from law enforcement seizures.
The UK has a passive Bitcoin strategy, holding $3.67B with minimal recent transactions.
Bhutan and El Salvador actively manage Bitcoin, with Bhutan also generating income through mining.
With the data provided that the US, UK, Bhutan and El Salvador have stored Bitcoin, but the US has the top ranking. Bhutan and El Salvador are also trying to collect Bitcoin by actively mining it, I think Bhutan and El Salvador want to beat the US as the top ranking country.