No regrets at all! Prior to the XR I had an 8+ and figured if I upgraded it'd be to the XS Max or whatever 6.5" phone was offered in 2019. I like big screens and really liked that the XS Max screen is bigger and maintains the width of the 8+ screen instead of being longer but slimmer. I was really nervous about potential XS Max connectivity issues, though (I realize they aren't universal and that the XR had the potential for issues too) and concerned I might end up being someone sensitive to PWM (I've had recent eye issues so I was especially concerned, more so than I might have otherwise been). I knew I could buy the XS Max and see if I had connectivity issues and/or eye issues and return it if needed but the more I read about the XR the more it appealed to me.
I went to the Apple Store, played around with the XR and really liked it. The XS Max is a beautiful phone and I did notice the difference in the look of the screens when comparing them side by side, but the XR screen didn't feel inferior to me, just different. I ended up going with the XR and love it! I haven't had any connectivity issues, I really like the screen size, the quality of the screen is fantastic IMO (the resolution is a complete non-issue for me and looking at the screen on its own I didn't/don't find myself thinking "I wish the screen were [brighter, had deeper blacks, etc.]"), call quality is great, and the battery life is incredible. I got used to FaceID quickly (I loved TouchID so I wasn't sure if the switch to FaceID would be a bit of an adjustment). I also saved over $550 going with the XR vs the XS Max based on the prices + sales tax where I live.
Very happy with my decision to go with the XR.