Sorry, you are going to have to choose between a "huge family drama" OR sucking up being miserable, stressed, & still having to supervise MiL's "childcare" to the detriment of your own work & peace of mind.
Bear in mind that it won't be YOU causing the drama, it will be MiL's unreasonable demands & shitstirring causing it.
You didn't want MiL's childcare, but settled on the 2 day compromise.
MiL doesn't actually do much childcare, because that's not really her interest - her interest is in getting her own way, shitstirring, & lying on your sofa disrupting your work with her loud phone calls, complaints, & lack of actual ... childcare.
You say you are anxious every night before the childcare, mainly because MiL goes out of her way to create discord between you & DH.
DH is not blameless here.
She has had her at her house a couple of times and that was better for me but my DH was worried about DD being there all day and that made me worried so I brought her home after lunch.
So ... he doesn't like DD being with his mother, & instead of stepping in as a parent, he instructs you to take over. Why does he get to impose this on you, as if your job isn't as valid as his?
My MiL is not happy and seems even more unhappier that she hasn't caused a huge argument about it between me and my DH.
He doesn't listen to you, & is obviously siding with his mother about an issue which doesn't affect him but is expecting you to suck it up so he doesn't have to disagree with his mother.
She keeps calling him and now he has suggested that we cancel the next two extra days with the childminder (which we've already paid for) so MIL can look after DD before she goes on her next two week holiday. I haven't responded to my DH on this suggestion.
Again - it doesn't affect him. It affects YOU, but he doesn't have his work disrupted, 2 anxious evenings worrying about what unpleasant remarks MiL is going to be making the next day, or spend 2 days underperforming at work due to having to pick up MiL's slack.
He is throwing you under the bus in order to pander to his mother.
First, you need strong words with DH.
My DH works at the office and so he doesn't appreciate that MIL doesn't actually do anything when she is here and actually creates me more work.
Stop buying this bullshit from him.
He knows damn well - because YOU HAVE TOLD HIM. He is simply choosing not to acknowledge it, because IT DOESN'T AFFECT HIM.
You need to tell him - again - how much this is stressing you out.
How anxious you are each evening before MiL's "childcare".
How disruptive she is in your home, & how much childcare she leaves to you.
How it is making you underperform at work.
How she makes obnoxious remarks, & lies on your sofa complaining.
Then remind him that he KNOWS MiL is incapable of looking after DD for a full day, as he won't allow her to do a full day at her own house.
Ask him why he feels it's OK for you to suck all that up.
Tell him that no matter what he thinks, it IS NOT OK & DD is going to the childminder she loves full time, you will no longer pander to his mother at the expense of your own mental health, & that he needs to back his own wife for a change & stop imposing his mother on you.
Remind him that HE isn't affected, & how unfair it is to dump his mother on you, pretending it's childcare, when it does nothing but make more work & stress for you.
Then tackle MiL.
There's no easy way to do it, but you can dress it up with how, when she comes to yours for childminding, she's so tired she lies on the sofa unable to actually look after DD, so you are going fulltime with the childminder so MiL can enjoy fun times at weekends or evenings instead.
Let her kick off, don't allow your husband to tell you who is allowed to impose themselves on you in your home office, & - at last - stick up for your right to be as unaffected by MiL's dominance display "childminding" as he is - the selfish git.