Like the others here I would recommend some sort of subterranean air circulation, lots has been done in the realm of passive greenhouse cooling - one thing to keep in mind is that in high humidity it's possible to get mold growth in the underground pipes so it's good to have a way of cleaning them. Look into Earthship passive cooling, the approach is to use convection to pull cool air into the building by venting the hot air through the highest point in the structure and it generally seems to be pretty effective.
As far as more traditional A/C systems, the lowest power ones I've been able to find utilize indirect evaporative cooling; essentially a swamp cooler that keeps the evaporated water separate from the cooling airstream, such as the M-Cycle design
https://www.achrnews.com/articles/108864-the-m-cycle-based-cooling-system - these essentially only require electricity to run the fan to circulate air and as such require significantly less power than standard air conditioners relying on compression cycles, however they have the major limitation of decreasing effectiveness with increased outside humidity (although this can be solved via a dessicant/dehumidification system prior to air intake). The other issue is that these seem impossible to buy anywhere. At one point there was a company called coolerado making these but they appear to be discontinued:
https://www.youtube.com/watch?v=PHSuFmmHpDM. A guy in Dubai has been 3d printing them and appears to be having some success
https://www.youtube.com/watch?v=r7LITeqLLwY, I might attempt to build one of these at some point in the near future for my partner's camper van (if I ever have the time haha) and will make a post here if I have any luck recreating the design. Here's an example configuration with a dessicant wheel inline for humid environments:
https://youtu.be/RqS6TXI-Nj4?si=1Pwjr5vQWqavVQCk&t=378
Direct sky cooling is another option (essentially materials which emit thermal radiation in a bandwidth that can escape earth's atmosphere, although these generally don't work nearly as well as standard A/C), several people have created formulas for a paint which can be created, however there is question about the long-term durability of these panels :
https://www.youtube.com/watch?v=KDRnEm-B3AI
Another potential avenue for person-level cooling is phase change materials which don't require much additional cooling, although again there is the question of long-term durability:
https://www.youtube.com/watch?v=Nqxjfp4Gi0k&t=1069s
The bottom line is that any steps you can take to optimize your house / space to make it generally cooler in the first place will be very beneficial, some best practices are things like: controlling airflow through the space efficiently, ensuring solid insulation and thermal mass, building partially buried structures (with extreme caution, working in even shallow holes is deceptively dangerous), having shades/awnings over windows, really any steps to prevent heat from entering the structure in the first place.
Hope you're able to find something that works, I second your frustration at the lack of a comprehensive off grid air conditioning approach
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