Are Guest Posts Worth? Especially for C-end Product Startups?

Hey everyone! I'm running a startup focused on productivity, recently i've been diving into SEO to promote my website. I've found that writing guest posts takes up a ton of time. Seriously, i can only finish one targeted article in an entire afternoon. The worse thing is that there's no guarantee that it'll work out. They might just reject you. So, I'm just wondering if it's really worth spending so much time just to get a dofollow link? Is it because i'm not good at this or doesit really take this much time no matter what? Love to hear if any of you have more effective ways to boost the DR of a website. Thx!