You need air to be able to circulate around fresh veggies. Closed bag always rots faster than an open one. Also storing green onions with roots in water can help they stay crisp longer. Lil paper towel to absorb moisture also helps!
Some things are just going to rot faster than others. Leafy greens especially. Part of why I prefer heartier veggies like brassicas.
Tangentially related but do not sleep on flash steaming. It is hands down the fastest and tastiest ways to cook a lot of veggies. Carrots, beets, aforementioned brassicas, lotta things steam up real nice. I do it over the stove with a pot and metal strainer but even just a glass dish in the microwave w/ a little water will get great results, if a lil soggier.
CONGRATS ON GOING VEGAN!
I’ve got many many tips from a lifetime in restaurants so feel free to reach out anytime!

btw