With Braiins OS you never disable the autotuning, unless you are repairing the hashboards.
And yes, it was normal to take 6~12 hours with those old x17 the first time. Just pick a sane power target, go low for better efficiency.
Do NOT ever use any firmware version beyond 23.01 with x17 miners, 23.01 is the FINAL release for x17.
The autotuning works great, but with change of seasons where I am, it goes into auto tuning for days on end (in springtime it seems the extremes in temp make it autotune more than needed). After the spring season, there is no issue with autotune.
My powertarget is 1Kw Braiins os shows 740 and at wall 599-615. I played around with the settings a bit and I don't think I can get much lower than 29-31 w/TH @21TH .. without autotune. Soon the temp will stabilize and I can set it back to autotune.
A couple of total restarts solved the issue I had.
Thanks for the heads up on the version.