What are some easy sewing projects for beginners to start with?

Knees, butts and patches….

Skirts are relatively easy. Lots of straight lines to sew, nothing too complex to cut out… And same with aprons. Definitely don’t try sleeves your first time!

If you go to a store that sells patterns, they should have a difficulty rating on them that could be helpful, too.

Get a skirt pattern with a gathered elastic waist. You don’t want to set in zippers, a waist band and make button holes for your first effort.

I always loved making throw cushions. Over time I got very creative with prints and embellishments, from satin ribbon accents to fringed edges, piping, complementary fabrics on the two sides, soft and squooshy versus tight and firm, etc. I’ve used quilted fabric, soft corduroy, plenty of sturdy cotton, and once even silk. One year I made a lot of them as Christmas gifts.

A cushion could easily be completed in one day (a few hours) and give a nice feeling of accomplishment, whereas something with a lot of pieces and fussy seams could take days or weeks.

The easiest are pillow cases, but it sounds like you many have progressed beyond that.
As @fireinthepriory says, find a pattern at the store that is rated for beginners.

. I second pillows and pillowcases, with fun trims. Easy window toppers are an easy way to change the look of a room. Or you could make a skirt out of neckties. There’s several different ways to make these.

The other reason things like cushions are a good idea is that they don’t have to fit you. Worst case you add or take away stuffing.

Shopping bags and purses serve this purpose, too. They can be as simple or as complex as you’d like to make them while you get a feel for different fabrics and techniques.