Hi Elias

For your first problem:

Ensure Top Alignment for Other Columns: Add the vertical-align: top; style to cells containing other column values, so they align with the first line of the description. Or use bootstarp call 

<span class="align-top">top</span>

For line space:

Reduce Line Spacing in Description: Use line-height to control the spacing between lines in the description column.

or use bootstarp
https://getbootstrap.com/docs/5.0/utilities/spacing/

here an example:

<!-- This is an example of a table row in the report template -->

<tr>

    <!-- Description Column -->

    <td style="line-height: 1.2; padding: 5px;"> <!-- Adjust '1.2' to control line spacing -->

        <span t-esc="line.description"/>

    </td>

    <!-- Other Columns with Top Alignment -->

    <td style="vertical-align: top; padding: 5px;">

        <span t-esc="line.product_uom_qty"/>

    </td>

    <td style="vertical-align: top; padding: 5px;">

        <span t-esc="line.price_unit"/>

    </td>

    <td style="vertical-align: top; padding: 5px;">

        <span t-esc="line.price_subtotal"/>

    </td>

</tr>