agoda booking worked for me, just make sure is a SHA PLUS + HOTEL, and tell the hotel in the chat from the app that you are coming with sandbox, flight number, etc, they will reply with full instructions,
ive tried to do direct from hotels, and they told me to use agoda, so agoda is fine, it worked for me, the important like we say is to upload very carefully all the dosuments and make sure teh QR is uploaded well, i got aproved 2 times, first time took long and had to write emails for that, seconf was automatic.
i undestand yes, i got all those direct links to pay in message from the hotel in agoda app, was very easy clear, also the vaccine QR is very important i think, then is automatic.