Hi Maks,
Decile Research is a feature within Decile Hub accounts. It looks like you've created a second user, with maks@geek.vc, that doesn't have access to any accounts. Your previous user, under the email maks@geek-ventures.com, is a teammate on the geek ventures account. You could either arrange for this user to be invited to the geek account, or sign in with the previous user. If you've forgotten your password you have the option to reset it during the sign-in process.
Once you've signed into a user with access to a Hub account, you'll see "Opportunities" in the new UI left nav, or "Decile Research" in the classic UI.