Thread moved.
In light of your niche and your comments
@bundymind , this seems like a good option -
But you have to see if its cost effective - you would probably need 3 hosts - 1 for each copy of the website to run on (These would need to be hosts that permit adult content) and then a third host to run the scripts used to detect if the live copy of the website goes down.
You could then have the script run every 5 minutes to check if the site is online - maybe with a curl request to the homepage or something similar (So that you can insure site is actually accessible rather than just checking if server is responding to ping, for example). Then if its down, you could use cloudflare API to switch records over to the other server.
Then have an rsync script that runs periodically (Perhaps daily) to copy contents from live server to standby server so that its kept up to date. You might need the script to copy files with rsync and then also dump and import the sql database.
You would also have to weigh up how much money you are losing with the site being down, vs the cost of running this kind of setup. Because the other simpler and cheaper option would be to set up an automatic offsite backup of the website and its contents - which could be run from a small and low-powered vps from any provider - and then just have an uptime monitor for the site, email notification if it goes down and then you just have a manual process for setting up a new host and transfering the site contents.
With my own personal backup strategy I can have a website back online within 10 minutes just by following a manual process of restoring backup. that might save you the ongoing cost of running two hosts. But again, it depends on budget and cost of any period of downtime.
If you don't know how to impliment any of the technical stuff then you can probably ask ChatGPT