I’ll take slower over ad-bloated every day.

If you’re talking about Google owned sites, there’s circumstantial evidence that Google sets their sites up to do that intentionally in order to gimp competitors.

For me, switching from chrone to ff around 3 years it felt the opposite. Ff opens so much faster. Also scrolling is way smoother.

That’s weird, something is definitely wrong. Are they set up in a similar way? The first thing that comes to my mind is: Are you using the same DNS server on both? Differences in DNS response time should be more noticeable than rendering time on most hardware. And I think Firefox doesn’t use the system DNS by default but I might be wrong. Do you mind checking? I’m curious now.