To create a beveled text effect, follow the following steps:
1: start by making your text perfectly mid gray (127, 127, 127 RGB, or #7F7F7F). If your text or graphic isn't gray, make it gray first. If you don't want to make a flat-colored beveled graphic, you can still use this technique by applying the colors to the finished effect after you create make it beveled.
2: add a faint vertical gradient clipped to the text. Just a little darker than mid gray to a little lighter than mid gray. Although this isn't necessary, it will make our text effect look nicer in the end.
3: right click on the layer or layer group that you want to apply the effect to open its context menu, then select Layer Styles... to open the layer styles dialog. We'll be adding a Bevel and Emboss layer style.
4: set the Opacity of highlight and shadow to 100%.
Note: for some reason, all areas of the text will be covered by either highlight or shadow, with neutral areas affected by highlight. If you want to keep the original color of the text, make highlight 0% opacity and use only the shadow. You can use the shadow as a highlight by inverting the angle and changing its color and mode to match that of highlight.
5: adjust the Size until the beveled effects cover the whole text.
You should now have a grey, beveled text.
Tip: by default, Krita uses 100% Depth which create aliased ridges at the center of the letters. You can soften the ridge by lowering the Depth, although it's not a perfect solution because it also changes the lightness of the effect.
Tip: adjusting the Altitude lets you control how much the bright side, center, and dark side are lit. Lower altitudes make the dark side completely dark, while higher attitudes make the middle part brighter. You can also make Altitude negative.
Observation: no matter which settings you choose, the beveled effect in Krita always creates ugly artifacts at the corners unless you increase Soften, but if you do that it just changes how the effect looks completely by turning it into a blur. This feels like a bug to me, but I think these effects were added to increase compatibility with Photoshop, so maybe this is just how it works in Photoshop? It tried the same effect in Photopea with similar results, so maybe this is just how it looks. Odd, I'd have expect it to be smoother. It does seem that in Krita the "Smooth" technique isn't implemented the way it is in Photopea, though. In fact, I'm not sure if changing the Technique does anything at all in Krita.
The next steps are similar to what is needed to achieve a duotone effect.
6: add a levels filter mask on the beveled text. Adjust the control points so the dark parts of the text are black and the light parts are white.
7: add a gradient map mask to the layer. Pick the colors that you want the beveled text to have.
Tip: vary the hue of dark and light color for better effect, e.g. by making the darker color warmer or colder than the lighter. It's worth nothing that you don't need to make a simple 2 point gradient. You can add more points to create a metallic beveled effect if you want to.
8: place the text in a layer group.
9: use layer styles on the group to add stroke and drop shadow to it.
Tip: you don't need to make the stroke black. For example, for gold text you could use a dark yellow or dark orange stroke.
