What is the "relaxed" standard of plain error review in an appeal involving an unpreserved objection to a sentence?

² To be sure, the typical plain error standard can often be "relaxed ... in the sentencing context because the cost of correcting an unpreserved error is not as great as" it would be following a trial. United States v. Haverkamp , 958 F.3d 145, 149 (2d Cir. 2020) (internal quotation marks omitted). But we have questioned whether it is appropriate to automatically apply this "relaxed" standard in every appeal involving an unpreserved sentencing objection. See, e.g. , United States v. Reyes , 819 F. App'x 41, 43 n.2 (2d Cir. 2020) ; United States v. Fuller , 801 F. App'x 14, 16 n.3 (2d Cir. 2020) ; United States v. Dupes , 513 F.3d 338, 343 n.2 (2d Cir. 2008). We need not decide which species of plain error review applies here since the result would be the same under either one.