Personally oid buy an older Janome or Lemair. I have had both, and they are tough and reliable. I have made curtains for two houses etc. I’m sure other brands can be recommended. Speak with a sewing machine repair shop to guide your final choice.
I think you’ll need:
A strong enough inbuilt light
Be able to remove part of the machine, which then, because that section becomes narrower, allows you to say, sew a hem on trousers
An inbuilt thread cutter
A reverse function ( I’m sure y’all have that)
A bobbin rethreading design that is simple to use
Easy to thread
A foot pedal with a power cord long enough to not be annoying if your’e sitting next to a high bench
Nice to have a lid that pops open and stores the range of feet
A bobbin loading system that is simple and fuss free. I’ve noticed they differ slightly, ie one was slightly more fiddly than the other
What you are sewing is also really important. With the right needle and a tough machine you can sew leather without dropping a single stitch (eg I made an ebook reader case out of an old pair of leather pants).
I think your biggest learning curve will be getting the thread tension right. Watch a video on that before you start.