Zhenya, I had the exact same problem. Used to keep a massive spreadsheet with my professional relationships because all of the contact management tools I tried were too sales-focused and way heavy for what I needed.
So my team built FollowUp, a lightweight Personal CRM that lives in Gmail. It brings contacts into your inbox so you can manage them as you interact in your daily workflow. We have both one-off reminders you can set on contacts, or followup reminders that help you stay in touch (you select how often you want to communicate with a person - if that time passes and you haven't emailed, we remind you to reach out).
We also have a two-way contact sync with Google that keeps your contact info consistent, and features like multiple notes per contact and recent convo history to provide more context on your relationships. If you're still looking give it a try and let me know what you think!