Flight was changed so now I have a 20 hour daytime layover at Hamad + lounge question

If it were some other time of year, I’d be so down to take a trip into the city and explore, but 43 degrees outside? I am not brave enough for that.

So, any ideas for things to do in the airport? I’ve had a layover there before and heard there were all sorts of fun and interesting things like a garden, but I never ended up finding them last time. Do I have to go to a specific terminal?

Also, I’m flying business and saw a YouTuber’s video where he showed himself checking into a sleeping room in a Qatar airways business lounge. But last time I was there, my lounge didn’t have these rooms, only a rest area with pods? There are multiple business lounges right? Which one has the sleeping rooms?