What 27-inch monitor should I get to upgrade from 1080p?

I'd start with a 27-inch 1440p IPS monitor. It's a nice step up in sharpness from 1080p without making the jump to 4K. Around 144Hz is a good target, though you don't need to chase 240Hz for RPGs and strategy games.

The Samsung Odyssey G5 G50D is one model to look at. Compare it with other 1440p IPS options in your budget rather than buying based on refresh rate alone.

For those games, a cheaper 1440p screen at 100Hz or 120Hz could be plenty. The MSI Pro MP275Q is one example worth checking. Compare prices with faster models, though, since sometimes the difference isn't very large.

Don't rule out 4K at 60Hz if sharpness matters more to you than a high refresh rate. It's a reasonable alternative for slower games, but check whether your graphics card can run the games you want at 4K. You may need to turn some settings down.

Panel type is worth considering too. IPS is a common choice for affordable 1440p monitors, while OLED costs more and has a risk of burn-in. Look at independent reviews of the specific model before choosing, especially if dark scenes in RPGs matter to you.

Budget and location would help narrow this down a lot. Monitor prices and availability vary, so a good deal in one place may not be a good recommendation somewhere else.