Brugge for 5 days

There are three train stations in Brussels....
https://www.brussels.info/train-stations/

The RS guidebook is very helpful on these things.

Brugge is in your title, but not on your agenda so far, I assume that is an oversight, because it is great day trip. Other trips depend on your interests, but there is something for everyone.

With 5 fully days in Brugge, you'll want at least 1 and maybe 2 day trips, possibilities are:
Ghent, 30-40 minutes by train
Flanders Fields battlefield with Quasimodo Tours (if interested in WW1 sights)

The most popular neighborhoods for lodging in Brugge are not close to the train station, but rather a 5 minute taxi ride, north of the train station. or a 20-minute walk (not recommended hauling luggage)--it's the area around the city center with the bell tower.

We stayed at Hotel Navarra Brugge 41 St Jakobsstraat, Bruges, 8000 Belgium. It was just off the main square. I'm not sure how far it is from the train station. We had a car. The hotel was really nice and so were the staff. We loved Brugge. Have a great trip!

I guess personal preference, but I would consider a day trip to Ghent from Bruges, but do an overnight in Antwerp. Bruges is nice, but not 5 days worth. Brussels is also great, or look at another small town.

Yes, the city centre in Brugge is quite far from the main station, I wouldn't recommend staying near the station if you're there for five days.

Consider the Hotel Carlton in Ghent it is less than 1/4 mile from the train station and more central to Antwerp, and Brussels than Brugges, reducing your travel time for day trips.
It is reasonably priced establishment and includes a wonderful made-to-order breakfast.

The proprietors are very congenial; they are thorough in their information about the area.
Many posters prefer to stay in Brugges and you may too. Just making the suggestion if you are looking for a hotel convenient to a train station.

The way I would explain it is that Brugge, Gent, Antwerp, and Brussels are close enough to each other that daytrips can be done in any way from anywhere. Someone who cares about cost should stay in Gent, or maybe Antwerp, which has more hotels and is slightly more central.

Even the most romantic couple does not need five nights in Brugge, which (compared to Antwerp) has a limited number of things to do. Sure, it's pretty. But so are parts of the other cities. I personally find Antwerp more central and plenty attractive. But you can't talk anyone out of Brugge once they've seen a picture.

As noted, distance from housing to the rail station is crucial for daytrips. Google Maps is helpful here.

Not certain what inexpensive means to you. In Bruges, we stayed at Huis Koning B&B, near the city center (that is a mile from the train station). I also recommend the Flanders Fields tour through Quasimodo. We enjoyed Ghent more than Antwerp and thought Ghent had more to offer, but both are worth visiting. I’m not a fan of Brussels at all.

Five nights in Bruges, as others have pointed out, sound like a lot! I'd allow no more than 3 nights; 2 would be fine even.

As a personal anecdote, I visited both Bruges and Ghent in a single day from Brussels, with a Brussels-based friend. We did not visit any museums, and we did not feel rushed at all: we had actually planned to stay in Bruges all day, but ran out of things we wanted to see by about 2PM, so decided to head to Ghent.