Debugging 3D website

My website is built with Next.js and uses OBJ/GLTF models, but it’s loading extremely slowly. After the models are loaded, the site lags. It works fine on phones and desktop PCs, but on some laptops, it’s extremely slow.

I need someone who is an expert in debugging to check via the inspector panel what the issue is and possibly provide remedies or fixes.

I am looking for someone with expertise in webgl, code splitting, lazy loading, optimize modals.