prevent tabstopping inside tagsbox template
MODIFY
WalletWasabi.Fluent/Controls/TagsBox.axaml
WalletWasabi.Fluent/Controls/TagsBox.axaml
<c:ConcatenatingWrapPanel>
<c:ConcatenatingWrapPanel.ConcatenatedChildren>
<AutoCompleteBox x:Name="PART_AutoCompleteBox"
+ KeyboardNavigation.IsTabStop="False"
MinimumPrefixLength="1"
IsTextCompletionEnabled="True"
Items="{Binding #PART_Border.TemplatedParent.Suggestions}" />

MODIFY
WalletWasabi.Fluent/Views/Wallets/Send/SendView.axaml
WalletWasabi.Fluent/Views/Wallets/Send/SendView.axaml
xmlns:behaviors="using:WalletWasabi.Fluent.Behaviors"
xmlns:c="using:WalletWasabi.Fluent.Controls"
xmlns:vm="using:WalletWasabi.Fluent.ViewModels.Wallets.Send"
- mc:Ignorable="d" d:DesignWidth="428" d:DesignHeight="371"
+ mc:Ignorable="d"
x:DataType="vm:SendViewModel"
x:CompileBindings="True"
x:Class="WalletWasabi.Fluent.Views.Wallets.Send.SendView"

prevent tabstopping inside tagsbox template