We're past Quake-level graphics, but competitive eSports games, by and large, have deliberately simple graphics optimised for readability over flare.
If you look at LoL, Fortnite, Valorant, Overwatch, they're all kind of the same — fairly flat light, bright colourful characters against a backdrop of pastels and otherwise muted background colours. Texture detailing is discrete and everything almost looks like block colours if you squint. Rainbow 6 Siege, CSGO, PUBG are the same, minus the colourful characters.
Even if those games didn't optimise their engines for performance over visual fidelity, their visual design would make them fairly light weight anyhow.
Another reason why those game graphics is like that is they want to support many devices, including very low-end Nintendo Switch and MediaTek smartphones. Toon style looks good in low quality.
The reason behind the 4:3 low resolution is outside of scope for ray tracing or performance overall: most of pro players found out that widened picture and thus player models are easier to target precisely in motion (AFAIK the phenomenon hasn't being studied properly) and you're limited by vertical resolution of the screen thus 960 is the upper bound for a common 16:9 1080p panel.
If you look at LoL, Fortnite, Valorant, Overwatch, they're all kind of the same — fairly flat light, bright colourful characters against a backdrop of pastels and otherwise muted background colours. Texture detailing is discrete and everything almost looks like block colours if you squint. Rainbow 6 Siege, CSGO, PUBG are the same, minus the colourful characters.
Even if those games didn't optimise their engines for performance over visual fidelity, their visual design would make them fairly light weight anyhow.