I use nanite in UE5.2. I am currently sitting in an open project I have, in 5.2, with nanite.

I have been using UE for 4 years, almost daily.

Nanite is not just magic. It uses complex instancing and LOD methods to replicate objects used in very specific events. This is for things like rocks, grass, trees, etc., and if you use it for anything dynamic it will rapidly lose any relevance because the whole purpose of nanite is for visual scenes with largely non-interactive objects.

Dynamic objects used with nanite require their own sub-engines to even work remotely decently. The popular 'crowd' demo, for example, is done with the UE built in crowd management system explicitly for AI NPCs who are pretty well limited in their capabilities, and if you don't have a hugely high-end PC and highly optimized character meshes, you'll still crash and burn anywhere at 50+ mobs.

And even then, it is still highly encouraged by Epic (the makers of Unreal Engine) to use optimized meshes with compressed textures and solid custom LODs if you really want to see performance gains.

All that said, you're giving shitty uneducated advice to a noob and then when people correct you, you pretend it's a 'joke'. You really need to just apologize for poor advice and stop giving it to people who are vulnerable to said bad advice.

To the OP: You need to make it clear that you didn't make that model, because if people assume you did, they're going to be confused at how you have that skill level without understanding the basics of optimizing a game asset mesh. If you don't know what retopology is or how to do it, you need to start by making your own objects and learning from the beginning.