So much this.
Whilst "no" is a whole sentence works in some situations, family relationships are far more nuanced. And some people are just really not with it.
My approach would be to agree times of arrival and departure ahead of the visit. I wouldn't bugger around making up excuses about being busy - I think that's almost as bad. If they wanted an explanation, I'd be completely open and say that I want / need the time to get the house in order and, with the working week being so busy, I must have some time to myself before the Monday grind starts. When people stay beyond that time it has a bad knock-on effect for the week.
If an extension was requested and I didn't want to acquiesce, I'd remind them about the time I need to myself being the reason it won't work.
If they tried to push back on that, I'd turn it around on them - I need my space and know you love me so I know you wouldn't want to start my week off on the wrong foot. I know you'll understand. It's been lovely seeing you and I look forward to the next time.
That sort of vibe. I don't believe in being dishonest. Be genuine. Explain. Reinforce how lovely it is to see them but you always ask guests to go by whenever because you know you need that personal time before the week starts. They can't take it personally, that way, they are ultimately told it's your preferred way of living in your own house. No one has a right to argue / disagree with that.
If, having done all that, they still try to push boundaries then it's fair game to be more direct without fear of repercussions. I have explained why I need this time, and you've not listened to me, which I find quite disrespectful / hurtful. It's disappointing but because you don't appear to respect me / my time, after I've tried really hard to explain what I need in my own home, it's a no to visits or you must absolutely be gone by time and, if you don't, we'll just have to forgego visiting.