well... There is Covid. that realy pushed things... Also, if we talking about 1st year and "only Sony made games", you can include DS Remake, Miles Morales ( Perhaps you can include Tsushima as crossgen, maybe? Last of Us 2 is Ps4, kinda unfair to include it on "PS5 first year").
Still, for a first year and considering "only Sony made games", solid year.