looking for this buck controller or similar to it. https://datasheet4u.com/pdf-down/A/P/W/APW8868B-ANPEC.pdf
Hello itronic,
looking at the documentation for RT8231AGQW, it does appear to have similar input and output voltages that may work, but it would depend on your application. The pin out does appear to be similar, so it is possible that it could work for you.