There's no way to play PS1 and music CDs on PS4 and PS5 because Sony removed that feature on an engineering level.
DVDs can be played. Sony absolutely locked PS2 disc support away because they don't want people using PS2 discs to get a digital copy installed for free or a lower price than on PSN.
The issue is that Sony would have to bypass the security of the PS2 disc for the data. I'm pretty sure Xbox and Xbox 360 games recognize the security for the sakes of backwards compatibility without going through it (jailbreaking it).
Lifetime Sales Predictions
Switch: 159 million (was 73 million, then 96 million, then 113 million, then 125 million, then 144 million, then 151 million, then 156 million, then 161 million)
PS5: 116 million (was 105 million, then 115 million, then 122 million)
Xbox Series X/S: 38 million (was 60 million, then 67 million, then 57 million. then 48 million. then 40 million)
Switch 2: 120 million (was 116 million)
PS4: 120 mil (was 100 then 130 million, then 122 million) Xbox One: 51 mil (was 50 then 55 mil)
3DS: 75.5 mil (was 73, then 77 million)
"Let go your earthly tether, enter the void, empty and become wind." - Guru Laghima
