I achieved the following result with these settings.
<RadzenChart style="width: 500px">
<RadzenColumnSeries Data="@revenue2020" CategoryProperty="Quarter" Title="2020" LineType="LineType.Dashed" ValueProperty="Revenue" />
<RadzenColumnSeries Data="@revenue2019" CategoryProperty="Quarter" Title="2019" ValueProperty="Revenue" />
<RadzenColumnOptions Radius="10" />
<RadzenValueAxis Formatter="@FormatAsUSD">
<RadzenGridLines Visible="true" />
<RadzenAxisTitle Text="Revenue in USD" />
</RadzenValueAxis>
</RadzenChart>
Bottom border radius is not supported though.