I see the mobile version even on my desktop. 1320px is way too late to change layout. It should change as soon as there is room for that layout.
I think there are big problems with these animations, I'm seeing a lot of white space. Completely white on load means it just looks broken. If you zoom or change orientation it seems to require a reload to make the animations work too.
Overall I think you should read up more about how and when to use animations to delight. Josh Comeau's blog would be a good read for you. He teaches how micro animations can be far more effective than animating all content like this. Cassie Evans website shows good examples of this too (using GSAP) https://www.cassie.codes/
Animating all content like this can have a negative impact on seo as well.
One last point - you're resizing html to 62.5% to make 1 rem equal 16px but you are not mitigating against the huge potential accessibility issues of doing this. I'm not going to go into it loads, but just really think about whether you need to do that. Is there any reason in the modern web why you need to change the established cross browser default and make rem into 10px? Do you need to calculate layouts by pixels at all in the modern web. Think about it.