Radar has much longer range than IR. Heat seeking missiles are usually relatively close range weapons, i.e., less than 20 miles. It’s not stated directly, but

Radar has much longer range than IR. Heat seeking missiles are usually relatively close range weapons, i.e., less than 20 miles. It’s not stated directly, but my read on this is the new UHF radars can detect an F22, but cannot track it precisely enough for a radar guided missile to hit. But, they can get a hypersonic missile to the general vicinity, at which point the IR seeker takes over. China and Russia have had 30+ years to find countermeasures to American stealth jets so I would expect these weapons are at least somewhat effective.