Inspector v2 is now ~95% backward compatible with v1 in terms of the Babylon APIs. The only things that are not backward compatible are a few things like options that don’t really have an equivalent in v2 because of design differences (enablePopup and enableClose for example, as the side panes always allow being popped out and closing them just redocks them).
So if you are already using Inspector.Show(...) or Scene.debugLayer.show(...), you can simply install the Inspector v2 package (e.g. @babylonjs/inspector@preview) and everything should still work.