It can be difficult to match an almond with a gray so I advise you to look for a color with more significant difference to the tub than the grays you've been looking at. Think about what colors you like. Maybe a coral, or a peach or plum.

Go to the paint store and pick up paint chips you like. Take them home and look at them carefully at different times of the day , in daylight and in artificial light. When you have selected your two or three favorites, buy actual paint samples. Paint them on large poster board and again look at them in different lights.

The selection of the right paint color is not an easy process. Take time. Do it carefully. You'll likely have the color on your walls for a long time.

You don't need to replace to change the color. If tile find a sub that does resurfacing. I had a high end client that downsized and did this and he was extremely please with the price and results. A sub who does fiberglass and acrylic tub repair can change the color as well as fix chips and scratches.

Resurface! Really works and you just have to use appropriate cleaners and tub mats that don't leave suction cup marks.