Looks.....familiar.....
It does.
I assume functionality and aerodynamics lead to a more or less common appearance whether or not any copying is involved.
Kind of like how wind tunnels have made most cars looks pretty much the same, regardless of manufacturer.
A re-skinned F-18 ?
It looks like the offspring of an F-22 and an F-35. Similar notional designs have appeared as what an updated F-22 would look like. Since the announcement for the Tempest was made just after Trump and US Defense Secretary Mattis visited, I have a sneaking suspicion that the US is about to announce a similar project and that the “Tempest” will be the UK variant badge for a US successor to the F-22.
If it’s the top plane in post #1, looks to be a single engine.