Yeah, unlikely to have open days any time soon, though there are still some estate agents that are doing 'batch viewings' (so people booked in at 3, 3:15, and 3:30) so similar effect. I think that is pushing things even with empty houses, but it's happening.
As someone who was largely looking in so-so areas with our budget, I'd recommend making sure there are photos of all the spaces -- if it says there is a garden, but no photos are up, it leads me to think they're hiding something (and the couple times I ignored that idea, I was right). Same with other rooms. Also, try not to use an someone that does that trick of squating down low outside or uses a lens to make things look bigger. It's really obvious if someone googlemaps the area (which tends to be unflattering to homes at the best of times) and raises questions of what other photo tricks were used. Same with photos taken with an up angle in all the rooms to maximize size, that's fine, but if that's done and then a couple aren't, particularly bathrooms - that brings up concerns about what's hiding - usually mold or water damage from what I've seen.
Speaking of, while I've not really cared about bedding and towels and posessions unless it looked like we'd have to clear it (seen a couple ex-HMOs), but making sure the window sills are cleared and windows coverings open both for lighting and they're common places for people to look for issues like mold or cracks. Having them covered, especially if there is an issue, can feel like you're covering things which can put people off. There was one we saw where the top window was blown and they'd just pulled the blind down halfway. Made the whole place feel dodgy after that while a house with an obvious leak from near a window frame and a blown window in the conservatory and they were open about it (to be fair, it was hard not to with the rain on that day) didn't put me off in the slightest, it was 'okay, repair jobs'.
It might be an idea to look at the many online lists of 'things to ask when buying a house' and make sure there is information there for the estate agent to use. A couple times we had 'oh, I'm not from the office...' as answer to our basic questions like whether the house had gas. Also, a lot of people like to check the heating & hot water so having that on and information on it is helpful, especially at this time of year.