But it's not "occasional" - it's twice a week and is turning into something that is happening on a regular basis and always right as the OPs DD is getting home from work. She has no chance to just have a few minutes to get herself together before the guests arrive and as they aren't her guests she has no say on whether or not they come at all or to ask them to leave if it's too much.
The OP says her DDs room is right off the lounge so she probably comes home and wants to make herself something to eat but doesn't feel comfortable doing so when guests are there as she will have to pass the lounge to go from bedroom to kitchen and either have to engage with them when she is not in the right headspace to deal with social niceties or totally ignore them which is just rude ... Equally if she wants to go for a shower then she might not want to have to walk back past the living room in a towel to get to her room (I have some aunts and uncles I am close enough with to walk round wearing a towel and not mind of they see me and other aunts/uncles where I would feel very awkward even just passing a doorway where they might see me in a towel)
OP, do you want the visits to continue at this frequency and if so is there any way change the timings so that the visits are either earlier, so they're leaving just as DD gets home, or later, so DD gets a bit of time to get herself together before they arrive? Or even alternate different venues - so some weeks they come to you, other times you go to them and other times you go out somewhere whether it's for a walk, a coffee etc?
I am an introvert with anxiety and work in a customer facing retail role. I am perfectly able to project an extroverted personality at work but it is exhausting so when I come home for the evening I am usually overstimulated and just need 30 minutes of quiet to switch off from work.
To do this I come in, take off my coat and shoes, have a shower, get into comfy clothes and then I make tea ... DD knows that this is my routine and when she's with me (I share custody 50/50 with ExDH) she knows that when I come home I will say a quick "Hey, how's your day been?" as I come in and then disappear to the bathroom/my room for 30/40 mins and then once I've had that "reset" time I will make tea and we will spend the rest of the evening together.
If I ever have friends/family over in the evening I will always arrange for them to come over no earlier than an hour after I get home so I have a chance to take some time for myself, make sure the place is presentable and rest for a short time before I have to host.