High FCP and LCP on a simple landing page?

[galaczi]

I am building a relatively simple landing page and having a hard time understanding what causes high FCP and LCP with SSR.

First Contentful Paint
3.7 s
Largest Contentful Paint
3.9 s
Total Blocking Time
10 ms
Cumulative Layout Shift
0.005
Speed Index
3.7 s

I am using Fowbite Svelte. The page renders fine if I block JS, so there shouldn't be any JS that should be awaited for rendering. Any idea how can I ponpoint the issue?