You already have two excellent bikes right in front of you, but I'm gonna tell you about something nobody else has really mentioned: the resale value thing. On a 125, you're probably gonna keep it for 2-3 years before moving up to something bigger, and that changes things quite a bit. The CB125R resells really well because everyone knows it and it inspires confidence. The YZF is cool but you're gonna lose a bit more on resale, especially if it's got scratches. Doesn't mean you shouldn't get it, but yeah, it's useful to know.
Personally I think you should also check out the Suzuki GSX-R125 or the Lexmoto LXR 125 - they're forgotten by a lot of people but they really handle well. The Suzuki especially is a good middle ground between fun and reliability, and insurance isn't more expensive than Honda. If you've got a tight budget, Chinese brands like Lexmoto or Keeway aren't great because of resale value and spare parts being a pain to find, so I'd skip them.
For insurance and maintenance it's true that Honda wins out, but honestly the price difference between the CB and YZF isn't that big in the end. What really matters is picking the one you actually want to ride every day, because a bike you love is a bike you'll maintain properly. Test ride both if you can, just to see what you actually like in terms of position and how it feels at the handlebars.