I dont’ really book hotels much unless it is for my job and when I do I find the best prices are from the hotels website itself and not the 3rd partiers. I’ve also heard horror stories of people booking from 3rd partiers and then get denied when arriving at the hotel with them being overbooked. So with getting better prices from the hotels itself, I always just book with them. Also if you did find a better price from a 3rd partier, I wonder if the hotel would match said price if you talked to someone at the hotel.
But when going on vacation I never stay at a hotel, or at least I hope to never stay at a hotel, so I use places like vrbo (main one) or other similar sites. My main location for vacation usually always has the by far higher price on vrbo, when compared going directly to the rental. On vrbo, you can see who the host is, sometimes it is a person and other times its an actual company going through vrbo. On my main location for vacation, it is a local realty company that uses vrbo to help find renters. So if I use VRBO instead of going directly to that realty website, it usually is always several hundred dollars more at VRBO, almost every time. I just got back from my main location vacation and saved almost 400$ by just booking directly with the realty instead of VRBO. VRBO adds many hundreds in useless junk fees like ‘hosting fee’s’ and other nonsense (which are separate from cleaning fees).
So in my experience going direct will almost always be cheaper, at least from what I’ve dealt with personally.