If you already use a password manager, why not use it for your TOTPs too? Someone already commented about bitwarden.

I use KeePassXC (on Linux) and KeePassDX (on Android) to store my TOTP secrets along with my passwords. Websites that have their input fields tagged correctly allow the browser addon/autofill service to let me autofill the TOTP too!

I've come from blindly using Google Authenticator, various game-specific TOTP apps, Authy, then Aegis, to finally looking up the TOTP spec, learning that it's just a set of default parameters and a seed, to storing it religiously in my password db, extracting the seed and params from a QR code if that's all I'm given.