Use local prop
MODIFY
WalletWasabi.Gui/Controls/WalletExplorer/SendControlViewModel.cs
WalletWasabi.Gui/Controls/WalletExplorer/SendControlViewModel.cs
@@ -937,7 +937,7 @@ namespace WalletWasabi.Gui.Controls.WalletExplorer
Global.UiConfig.WhenAnyValue(x => x.IsCustomFee)
.ObserveOn(RxApp.MainThreadScheduler)
- .Subscribe(x => IsCustomFee = x || Global.FeeProviders.AllFeeEstimate == null)
+ .Subscribe(x => IsCustomFee = x || !IsEstimateAvailable)
.DisposeWith(disposables);
this.WhenAnyValue(x => x.IsCustomFee)

Use local prop