Bottom line is, Saudia doesn't have a lounge in Bangkok BKK airport. They use the Miracle lounge opposite gate G2 and you need a lounge invitation card to be able to enter it. I didn't have one because I remained airside at the airport and did not visit the check-in desk in BKK, but they let me in anyway. This is an interesting subject, the business of not having to immigrate into Thailand and remaining airside if you have a connecting flight on a separate ticket. It is totally doable if you have hand baggage only and have checked in online in advance. On my outbound trip Thai Airways International would not issue a boarding pass, just a confirmation of check-in, but that wasn't a problem. However, the ersatz immigration people checking documents to let you into other airside parts of the terminal enjoy the small bit of power they have, so watch out.
The Miracle lounge had a few stations with hot food offerings, but between what I'd had for breakfast and what I had on the previous Thai flight I just had a couple of finger sandwiches made of sliced white bread and an Oolong tea. I concentrated on working my way twice through the beer selection, because I was about to board a dry Saudia flight. Certainly, there were plenty of places to sit, but great comfort was not on offer. Staff were friendly enough and I consider that to be quite important. I had about one hour in this lounge, which was enough.
Dining area in the Miracle lounge in Bangkok BKK airport
The food buffet was okay, nothing more
At least there was some food, because many lounges have packeted snacks only
Self serve drinks from a well stocked fridge
A quite acceptable beer selection in the Miracle lounge in BKK airport
My Saudia flight was waiting outside the terminal building at Bangkok BKK airport