I am really impressed by that machine Onebyone mentioned which is still readily available, or the current model which is about $100 more, when I looked pre-Black Friday the current model was about $650 on Amazon. I am seriously considering that as my portable machine replacing my current one... it has features I really like that usually aren't so available in the price point.
For a lower price point, I do like Brothers. You want a mid-level machine. They are light, very easy to learn/switch machines, have threading assists, can buy feet at Walmart even! For awhile during covid I made masks on a bottom of the line brother because it was working -- it was so light I ended up using blue tape to stick it to the table so I didn't have to run after the machine all the time.
When I bought my portable class machine I wanted an all mechanical machine because it was the fancy parts on my Bernina that kept failing and when the Brother's died it was typically a plastic gear or whatnot. I wanted a price point around $200, and bought an Eversewn Sparrow 15 about 2 years ago. It is light, it is mechanical, it does have some stitches. It is for me slow and louder than the other machines that go to class, I don't know if I would recommend that model to you but you might want to look at Eversewn for model/price comparisons.
https://www.eversewn.com/