Is 10% as a Tech Founder a bad deal or could it be reasonable?

Hello everyone! I was recommended to two persons that are starting a business within fintech where I would be cofounder and responsible for tech. I have a masters and been working as a consultant for a decade in various clients, big and small. Their proposal is 10% for me and 45% for each them. They have been CEOs for a startup incubator and have a lot of experience in getting investments and building a company. They don't have a prototype or any customers yet but they have about 500.000€ in promised first round investments. So basically everything is prepared to be done so it would be up to me to build it alone from the start as CTO and then with time the team would expand if everything works as expected. Now the talks have been that due to investors and how it's unsure on what my role will be in the long run (since vesting for everyone is 8 years) , 10% would be reasonable. My first thought was to have 33% each but maybe that's not very common in all scenarios especially like this when the investors are basically only doing it since they wanna invest in the two cofounders and trust them? Sorry if I've missed anything important to share but feel free to ask and I'll answer ASAP, I'm very new when it comes to being a cofounder in the world of startups