How is this different than adding DEI requirements, the inability to study schedule 1 drugs, or the restrictions placed under the Dickey-Wicker amendment?

Federal grants have always been subject to politics.

It's different because it explicitly prohibits deferring to peer reviewers and explicitly requires that grants must "advance the President's policy priorities". Previous restrictions were guiderails for or additional screens on top of the underlying merit-based review; now the merit-based review is secondary and the primary criterion is whether the President's minions like the proposal.