Regarding the vaulted ceilings - as far as I am aware it is specifically the ‘Vaulted Ceiling (single)’ that seems to have this problem (though might still be worth checking others to be sure).
Spider webs gained collision (according to reports) with the upgrade to UE5 - I know for a fact it applies with the version recently given away for free in the bazaar - possibly it applies to all spider webs, possibly just some (reports have been a little unclear).
Curtains always had collision, but it would be a nice upgrade if they didn’t, especially given Living Settlements.
Additional ‘collision’ reports I can find -
Chest lids have collision and can cause players to be launched into the air - since upgrade to UE5
Some placeable items are missing collision since the upgrade and cannot be interacted with at all after being placed - link shows some specific item numbers
Thralls have been falling through foundations (again) since 15 September - seems to be directly related to thralls placed on Siege Cauldrons (and possibly archer posts) - link
I hope that helps 