Ask HN: Rest&Vest or New Opportunity?

I understand this is going to ruffle some feathers around privilege and what not. I apologize but want to hear your thoughts on opportunity cost and the likes. I have unvested options worth 400K with my current employer but have potential opportunities with two other Series A startups. My skills are suited to a small company as opposed to a large company that I am at now. Everything moves slowly in a large company. However, I am unable to leave and take up the opportunity at these smaller companies since I’ll be walking away from guaranteed RSUs (company I work for is publicly traded). So, for the next three years should I just rest & vest ? At my company I mostly “manage” and don’t “do”. I am someone who likes and thrives in “doing”. I am sure others might have experienced this in the past. How did you think between the two things or about the opportunity cost in general ? P.S I am not going to pretend that money isn’t important. I am the first one in my family with a Master’s degree and 400K (current value of stock) is lot of freakin money and walking away is hard but I also know that I can probably make that in the course of my career, if I doing what I like doing rather than being a cog in a bigger company. Thank you for your answers and attacks ! :)