I'm traveling often and want something better than the old fashioned lamp timers I'm using.

I looked into Apple Home Kit stuff, Google, and Alexa, and I don't want a "smart" speaker. I have an iPhone, MBPro, and Apple watch and I almost never use Siri. I don't want an open mic in my house (even though I have one on my wrist and one in my pocket  ).

I bought some smart plugs that I can program with an app for $3 or $4 a month, but I would also like to get relays to control my outdoor lights which are from different manufacturers and probably won't work with the app.

Does a "Dumb Hub" exist? Is there a hub that doesn't use voice commands?

I have a Home Automation system called https://homeseer.com  This system integrates with many different smart devices.  It has a cloud function and can be integrated with voice. I run this software because even if the internet is down it will still manage my house automation functions (it is not dependent on the cloud).  I do not use any voice integration for security/privacy reasons.

I haven't looked at this in a very long time, but IIRC you could use an Alexa app to control devices through a user interface rather than (or in addition to) through voice commands.

I don't remember whether or how you could disable the voice command ability, but I'm guessing that it may be possible to do so (if you 'trust' amazon, that is).

Home Assistant is what you seek. It is open source, needs nto subscription or server outside your home.

TP-Link makes some smart devices (bulbs, switches, plugs, etc.) under the Kasa brand.

https://www.kasasmart.com/us

Hubitat Elevation or Aeotec Smart Home.