20 years ago I actually put in the top two-thirds of two telephone poles in our garden for washing line & more importantly Mexican hammock; bury 1/3 of cut-down pole, wedge in with rubble, dry mix. Don’t know if that’s the best way, but they’re still there & plumb (it’s the pic that’s wonky honest)
I was planning to go side wall, house and back fence post (there are some concreted in fence posts although I suspect they technically belong to the house out the back) to hopefully avoid any disasters.
Whacking some big poles in would be ideal but sounds like a lot of hard work.
The sail will be fine except on the fence, it could actually pull that down if you forgot to bring it in when the barometer is sinking.
Probably need to sink a post into concrete or something ( @Colin_the_Bald ?) to anchor to.
I had one for a while*, didn't need a ratchet strap: it's a good opportunity to learn some rope craft - modern tensioning knots are very cool.
It's also good to note that you can use your anchor points to rig a hammock for full relaxation skills.
*See above about fence and barometer.