Looking for a bike to commute to work. Confused and overwhelmed!

Hi! I've been through a few bikes in recent times. Two road/racing style bikes which were stolen. I also tried an ADO Air 2 Pro folding E-bike. I found that the road bikes, while nice and light, were a bit uncomfortable in terms of the sitting position. And, the E-bike was very heavy, sort of clunky, and charging it is a pain.

My commute isn't that long and is fairly flat. I don't know a whole lot about bikes though, so I'm wondering whether some kind people on here can help me with all the options 🙂

I've been reading a bit about single-speeds and 2- and 3-speed bikes, which seem nice for being lighter weight and lower maintenance. And also, honestly, I quite like the aesthetic.

Some things I've considered:

• Bobbin Kingfisher: https://bobbinbikes.com/products/kingfisher This seems nice, and has a huge discount (is this a *real* discount?) but I can't find any reputable looking reviews. Also, it's 12kg. I don't have a good gauge of how much that would be "in practice" — would this feel quite heavy?
• Tokyobike https://tokyobike.co.uk/products/tokyobike-mono Another rather nice looking bike, a bit more expensive (considering no discount). Single-speed. What do people think about single speeds? For context (if it helps at all) I'm in Nottingham, so like, there are some hills, but I can mostly go along the canal.
• A Dutch bike from gumtree, second hand, £120. I have no idea about this bike, even what it is. But it's a 3-speed. Does this seem like a reasonable price?

To be honest, though, I don't even know where to start looking seriously. There seem to be so many big companies who make bikes (plus things like Halfords/Evans/Decathlon own-brands of course), and also lots of cute little boutique bike manufacturers (I really like the feeling of these).

I'm looking to spend somewhere probably between £200 and (at a stretch) £600, but around £400 feels about right.

Any recommendations or tips? Many thanks!