OK, so the Eero mesh system is your "main" router and Wi-Fi network.
I am not recommending that you try to turn off the Wi-Fi on the Time Capsule because this may not allow you to connect to the Time Capsule using AirPort Utility to make any changes to the settings on the Time Capsule. It would be better to simply "ignore" 'the Wi-Fi on the Time Capsule and use the Eero network.
We can tell you how to turn off the Wi-Fi on the Time Capsule if you want, but if you find that you cannot access the settings on the Time Capsule using the Eero wireless, the only only option would be to connect an Ethernet cable directly from your Mac (assuming it has an Ethernet port) to the Time Capsule.
If your Mac does not have an Ethernet port, and you find that you cannot access the settings of the Time Capsule using AirPort Utility, then you will have to reset the Time Capsule back to factory default settings and then set it up again.
That's a lot of work, but if you want to try.......the decision is up to you.