I see. However, as mentioned, you can place the Shortcode Block within a Container Block of its own as shown in the screen recording I sent above. Through this, other Blocks wouldn’t be affected.
Well, all code/blocks added affect performance, but this small change shouldn’t have noticeable effects.
An alternative would be to use CSS. But, you would need to add the shortcode through a Hook Element. For instance, here’s a thread discussing how to do it: https://generatepress.com/forums/topic/style-yoast-breadcrumbs/#:~:text=1%3A39%20pm-,%231040701,-EDIT%20%7C%20MOVE
This also adds lines of codes to your site, but then again, they should be minimal to no effect to your site’s overall performance.
Hope this clarifies!