Demon Slayer Season 4 is Over 

I have the same top 4 as you, also same feelings on ep6. Others: ep4 at #5; ep1 at #6 and ep3 at #7. I understand your feelings on Sanemi & Obanai seeing the Infinity Castle, but I think they still couldn't have done anything to prepare for that moment, because: 1. The nature of that place is way beyond human understanding, even for Demon Slayers (Hashira level even) and they couldn't do anything to prepare for it. 2. What little they saw was proof that demons have disappeared, probably until they "...find Nezuko" and this is the chance to boost the stats for the overall corps. 3. The scene of them discussing what they saw and trying to make sense, was good enough for me, because it makes opening fight scene canon and Sanemi went again to check on it multiple times. 4. The finale was so perfect and well executed story wise, like Muzan had a plan in case things went south and the Hashira & Tanjiro simply had faces written "what's happening...?", while still boiling with rage over Kagaya & seeing Muzan. So much was happening in a space of a minutes.

UGHGHHGH I FEEL LIKE INFITITY CASTLE ARC STARTED TOO EARLYYY

Im not doing my hole list but ill say my top two my number one is episode eight just wow again probably my favourite episode ever BUT IN MY OPINION BECAUSE I LOVE MUICHIRO SO MUCH episode to bring a smile to someone's face and that episode really did that is my opinion if u haven't noticed muichiro is my fav character ❤

the season could have been peak if tengen & muichiro had their trainings in one episode and mitsuri and obanai got an episode half and half too. sanemi's ep first half could have been anime original training and second half genya scene (though in an ideal world, they could adapt the light novels, but we all know that's not happening) giyuu's backstory ep had so much potential to be the best backstory episode, but to me the choppiness of the first half until tanjiro's monologue about rengoku had so much room for improvement. i loved the scenes of tanjiro literally following giyuu and going "giyuu san! giyuu san! giyuu san!", but everything besides that

i think the lack of kanao was disappointing. ufotable gave thengen and muichiro whole episodes but kanao couldn't even get one additional scene?

I didn't really like how much Ufotable stretched out some anime original scenes, especially Giyuu's, Tengen's and Muichiro's episode. I would have much preferred if they just animated the light novels as a fun little side story.