So many dev folk hate magneto- what’s actually better?

I’m a business owner. We have a magento site. It’s a very complicated site with a lot of customization including “2-sided” marketplace functionality. We’ve spent a ton. Whenever we speak with someone outside our org, they say magento is old and far from the best. So- ok, what’s a truly robust alternative. We first tried Shopify and couldn’t have done we what did as quickly etc, so Shopify’s out. Help pls. Thx!