4K or 1440p for a 9070 XT when reading on monitors strains my eyes?

For your mix of reading and story games, I'd look at 27-inch 4K first. Text will be sharper at the same physical size, and you can use desktop scaling to make it comfortable to read without giving up that extra pixel density.

The catch is gaming performance. The 9070 XT can run games at 4K, but 80 to 90 fps isn't guaranteed in every demanding title. You may need lower settings or upscaling, and support varies by game. Check benchmarks for the games you actually play before committing.

I'd go 1440p if 80 to 90 fps is the priority. It puts less load on the card, so there's more room to keep settings up or use less aggressive upscaling. You can still get a 27-inch IPS, but don't assume a different panel alone will solve the reading issue.

Try not to make the choice on resolution and panel type alone. Brightness, text size, contrast and how the display handles its backlight can all be worth checking when you're sensitive to a screen. Mini LED isn't automatically more comfortable for reading either.

If possible, test the monitor with the kind of text you normally read, at your usual distance, for longer than a quick glance. Adjust the brightness and scaling, and follow up on the reading glasses advice too. The right combination may matter more than the spec sheet.

4K with upscaling is a reasonable middle ground for games, while the desktop stays at native 4K for text. Image quality and frame rates will vary by game and upscaling mode though. Frame generation can make motion look smoother, but generated frames aren't the same as a higher native frame rate for responsiveness.