Can this be made without an instapot?

For this recipe and futures, keep in mind that most instant pot recipes are usually speeded up versions of old-fashioned stovetop or oven recipes, so yes make them with regular pots/regular heat.
For futures, if you want directions for regular (not instant pot) cooking, look for a similar recipe on the web.
For this dish (butternut squash and red lentil soup), you could this recipe from BBC Good Food site.
https://www.bbcgoodfood.com/recipes/spiced-lentil-butternut-squash-soup