See if you can handle them, either at the range or the local gun shop, before making a decision.
+1
Go put your hands on both of them. See if you can put each on your hip where you'll carry them. See the triggers on both - they are very different. You may like one better than the other.
My own personal findings:
Ergonomics: Glocks do not fit my hand at all, and I was considering the G26 myself before I actually tried on out (and hated it, deal killer for the G26). But this is an individual consideration, you may love the feel of the G26. The p250 felt right, but opted not to go for it for other reasons.
Trigger pull: I think you'll find the trigger pull of the G26 to be better than the p250. Tired the p250 out and disliked the trigger (especially compared to my other Sigs). Deal killer for the p250. And then there are the lingering stories about p250 reliability, etc... (at least the early ones)...
This would be the first time I'd ever used a Sig pistol and was able to turn away (have the p220, p225, p226, p228 and p229 and swear by them, and am going for a 2022 later this year). The Glocks have never felt right in my hand, and I've been much, much more accurate with Sigs than Glocks. I was hoping the G26 would have changed my mind, but it just was not to be.
So I ended up with neither. You might have a totally different experience, and end up with both ...