Some people work on switching day and night patterns for the baby, so there is lots of being awake and eating while mum is home, and mostly sleeping and not feeding while mum is away. This has its own downsides, of course, but it is something that works for some people.
More realistically, you are probably going to use bottles in the daytime, whether they have formula or pumped milk in them. Do not start the bottles too soon. Wait until a week or two before you go back to work. Nipple confusion is a real thing that can lead the baby to reject the breast for the bottle. The longer you wait the more likely it is the baby can switch between the two.
It is probably a good idea to keep the baby up a little later at night once you start work. You might even have a normal wakeup of 9 or 10 am, and you stop by and wake the baby for the 7am feed, then go. While this won't give you peaceful evenings like the families who put the baby to bed at 7pm, it will give you one or two more nursings every evening and little less pressure on you to get your mothering into a short period of time before it is baby's bedtime.
Whether you pump or use formula is a personal decision. It can be hard to find a place to pump at work, and hard to bring the pumped milk home each evening. I would put that decision off until the baby has actually arrived and you get an idea for how tired you are and how easy you find nursing. If you drop all the daytime feeds at 3 months and don't pump, using formula, your supply might adjust or it might not. Pumping ensures your supply will continue. (BTW, don't confuse the nursing-got-shorter-and-I-don't-swell-and-feel-sore-when-it's-feeding-time phenomenon with losing your supply. At about 4 months most of the physical issues some women get in early nursing go away, and the baby gets really efficient at getting milk out, and sadly some women think this means they're losing their supply.)
If you do intend to pump about half your baby's milk, get a serious plug-in pump with good power. Battery pumps are for using on occasional outings without the baby, and are as much about relieving pressure and keeping up supply as they are about getting milk. You can rent plug in pumps on pretty short notice, but look into it now to make sure you know how to get one.