to eliminate all your problem whether is it government, excluded merchant code, all you need to do the following:
install grab app
add one card into grab pay
top up grabpay wallet using one card
pay using grab pay and your one card statement will show it is coming from grab instead of hospital, government, excluded merchant and etc...
make sure you hit $500 min every month.
on top of that, I applied for grabpay card and add the grabpay card information into my Samsung pay.
so I earn cash rebate for my one card, one bonus interest, grab points and Samsung pay points(used to earn additional 5% for Grab transaction but I think they revised it and it doesn't apply to wallet top up anymore this march 2020).
if i add grabpay card to favepay and hit the minimum card spending of $500, i get all the rebates, interest and points and also favepay cashback.
hope it helps!