Hi ,
In the post i sent you above they are talking about the platform rest in home assistant which can integrate your SP3 HW , there is also an example of the code they used . Did you test that ?
Unfortunately I cant test from my side since i do not have the HW but might be I can give little help
if you will test it
The post about the using rest
The rest sensor platform
Give it a try and if this is important to you and you faced issue then directly send a mail to the guy in the post who made it work ( his name is chrisrosenkreuz23 ) .