another alternative would be to host a “hospitality suite” during the break.
Does the venue need 2.5 hours or do you want that break for photos and outfit changes? If it’s the latter, perhaps you can knock it down to 1.5 or 2 hrs, especially if you don’t intend to go to additional locations for photos.
If you or your parents/soon to be in-laws have a large room or set of rooms at the hotel, you could set out snacks and beverages in kind of an open house style so that anyone who doesn’t have their own room to go to or who would prefer to socialize than take a break can stop by and hang out. It would obviously need to be a large room or suite, but perhaps this could be a good excuse to upgrade your suite to a really swanky one? Lol
Or, yeah, just do the basement or have cocktail hour in the ballroom.
Whether guests are entering the ballroom first for the cocktail hour or for the reception, anyone who is going to be wowed will have that wow moment. I’m confused about why it is important to you to have that moment happen as they enter the reception instead of cocktail hour? Cocktail hour is basically just part of the reception anyways, is it not?
Also, for photos and stuff, a lot of couples have cocktail hour specifically to have somewhere for their guests to go that is hosted while they are off doing photos and stuff. It seems a bit odd to have a multi hour break followed by cocktail hour and then the main reception. Why not just have cocktail hour during the break or scrap it altogether and just go straight into the reception after the break? Obviously you can have some time for people to settle in and grab drinks, mingle, etc before beginning with dinner or any of the reception program, but it doesn’t need to be a formal cocktail hour.
ETA: chiming in to add that I also disagree with the overwhelming sentiment on this board regarding breaks. They are super common in every social circle I’ve ever been a part of and I have only been to a couple of weddings that didn’t include a break between the ceremony and reception (I consider a hosted cocktail hour as part of the reception)).
Most weddings I’ve attended had a break that was anywhere from one hour to two hours in length, but typically not any longer than two.
As long as I have somewhere to go to relax and freshen up I actually prefer that there is a break. In your case, more than half the guests are staying at the hotel and one could assume that most of the others either live or are staying nearby or are friends with or related to people who are staying at the hotel, so would probably have somewhere to hang out anyways.