Don’t listen to that fool. You are perfectly qualified to care for a cat. I’m probably less qualified than you, and my cats are happy and love me.

Don't listen to one person, lots of cats love being the only cat, I had two at one point, ended up having to separate them because one wanted to play all the time and the other hated it and wanted to be left alone! Just like people, you can't put everyone under the same umbrella. Some cats want company, some don't. You need to find one that suits your needs.

I edited my comment after with this because I thought I was coming off too harsh against the idea, and even this I would soften further:

Edit: it is different if you adopt an elderly isolated cat that would otherwise be put down. In that situation, you'll still be providing them with a life, but if you do get through to them, they will bond to you, and it will still make leaving for trips difficult, even if they're used to your daily absence. A support network is inherently more flexible and robust then a support pair.

The fact that you're putting this much thought and consideration into it, signals that you would probably be a very good cat owner, and I don't think you should write the idea off.

Just, try and find a cat that seems independent, and 6 months or a year in, look back and reconsider if it would actually be that much harder to add a friend to the mix.