Your current Asus is an IPS panel with relatively poor properties - including, of course, the contrast (see 1st link - although it is the 27" QHD model, it is otherwise comparable to yours). I can't understand the criticism of the sharpness, as your 28" is 4K and the pixel pitch is therefore very small... but all in all, your current 144Hz IPS monitor is worlds apart from a 360Hz OLED monitor like the XG27 or the G6.
You can't demonise the manufacturer because of a poorer display technology (IPS) ;) The XG27 from Asus has better PS5 compatibility than the G6 from Samsung (see 2nd link). Both are not much different otherwise, as they use the same panel (from Samsung - developer and manufacturer of QD-OLED panels). The difference lies elsewhere: calibration, features, OSD, design, ergonomics, connections, coating (matt for Samsung, glossy for Asus) etc.
Just be aware that you are downgrading from a 4K monitor to a QHD model, so 1. the pixel pitch will be larger (blurrier) and your 4K signal from the PS5 will be downscaled (again less detail). However, the picture itself is MUCH better, much richer in contrast, poppier, sharper (in terms of motion blur aka streaks) due to OLED technology and 360Hz and therefore also more stable in terms of viewing angle.
What I personally don't like about QD-OLED is the "Ambient Black Level Raise" - I only have WOLED from LG, which doesn't have this "problem". But that's another topic.
https://www.rtings.com/monitor...
https://www.rtings.com/monitor...