@RuffleCrow before my daughter was born, I spent years living away Mon-Fri for work, so I am an adult who knows what it’s like - and chose - to have 2 homes.
I’m not going to say it’s fine for everyone - it’s not just about practicalities, but also personality. But I think you also shouldn’t assume it doesn’t work for anyone.
My daughter happily goes to and fro between her 2 homes. I know I have a vested interest in believing that, but I can honestly say there has never been a problem from ages 6-11, and she isn’t one not to speak up 
The dates she goes aren’t fixed due to both my and her father’s shifts. She doesn’t care. In the morning she’ll say “where am I tonight?” It’s in a shared calendar on her phone, but she just doesn’t care, would rather just ask in the morning.
She has some control - I’ve had a Sunday afternoon phone call from her “mum, stepmum is doing a roast - I love roast - can I stay til tomorrow instead?”. Yep.
She has to do a school NSPCC exercise last year, where they wrote a list of places where they feel safe. She wrote “my 2 homes”. She flies around happy as Larry - 2 homes, both with all the stuff she needs, and an adoring parent. Frankly, given that you can use a Netflix account anywhere, 2 homes is no issue 
I know I have been very lucky with her personality and her dad having the same child centred approach to flexibility. We never have to drag her away from something fun because it’s drop off time - we just call and delay. That’s rare - but knowing you can is great. If she gets a good sleepover offer, he won’t say “that’s my night, no”. Instead we have a nice easy convo: “she’s been invited to L’s on Sat - is that OK? How about she does Mon & Tue with you not just Mon?”
Please don’t think - you and other posters - that it’s not possible for a child to feel happy and secure and perfectly at ease having 2 homes.