I think you can now clearly see the pattern I mentioned - heavy games that have to be upscaled from below 1080p will rarely give good results at this stage.
Low base res is just what PSSR struggles with (and so does DLSS still but it does a better job given its maturity) and it will get better at it but the reality is this is just paid betatesting of PS6 tech but Sony ingenously made people pay them, not the other way round.
When you think about it, they mostly showcased games that were bound to be better because they had already run exceptionally well on the base hardware and while I wish everything was as good as Stellar Blade, it just won't happen.
Games are getting more demanding so it'll be a mixed bag for the foreseeable future and it's no coincidence the worst offenders are upscaled from as low as 720p, like this one. SH2, Survivor, AW2, Avatar etc. have shown this as well and that's why devs are struggling.
Even in GT7 that's had a great patch, you'd only use PSSR if you want cockpit RT, otherwise the only thing you're getting is a fuzzier image.
And let's not forget PSSR takes resources to use as quite a chunk of the additional grunt has to be used to offset the lag introduced by the upscaler.
TL;DR: The tech will be fully leveraged by the PS6 as it will have matured by that time and the additional grunt will allow for higher base res -> cleaner upscalling -> more power left for improvements in other areas.