As a rule of thumb, for a 1st commuter bike or a 1st bike in general, go to your local bike shop. As someone mentioned above, keep it smple.
Bike shops usually keep a range of sizes, also basic accessories like spare tubes, a little pump, patches and tyre levers. If required, buy a helmet.
I would start with a 90's rigid mtb with 26" tyres, rim brakes, mudguards and a rack, if possible. All independent bike shops sell them, more or less in this configuration.
These bikes are staples in the commuter world for a reason. Yes there thousands of options but this is the easiest/cheapest option for a ready to go bike without taking a big financial loss.
They are also not a priority for thiefs if you're in a high crime area, unless the bike is blinged out. If you find one that you like (oh yes there is such a thing here's some inspiration
https://bikerebuilds.com/bikes) go for it, it will help you mentally as you will want to ride more.
Once you found a bike, commute for a few months as often as possible and leave the bike alone, don't change/upgrade anything. Clean it and lube the chain once a week. After a few months, your needs / requirements will surface as well, which is usually different gearing for the terrain you're riding, tyres, handlebars etc.
If you don't like it talk to your bike shop, most bikes shops will take back/trade in a commuter bike. Worst case scenario, you should recover some of your money or put it towards another bike.