Here is my code for easy reference  (I commented a few things out but did try to set radius to different sizes, numeric values, etc, all result in this error).

import {Button} from '@rneui/themed';
import React from 'react';
import {StyleSheet} from 'react-native';

export default function MYButton(props: any) {
    return (
        <Button
            buttonStyle={[styles.button, props.buttonStyle]}
            titleStyle={props.titleStyle}
            title={props.title}
            type={props.type}
            onPress={props.onPress}
            disabled={props.disabled ?? false}
            loading={props.loading}
            icon={{name: props.iconName, color: props.iconColor}}
            // loadingRight={props.loading ? props.loading : true}
            // radius={'xs'}
        />
    );
}

const styles = StyleSheet.create({
    button: {
        marginBottom: 7,
        marginTop: 10,
        // borderRadius: 20,
    },
});