I feel more relaxed sitting next to my friend rather than across from her.
I find it more comfortable sitting side by side with my friend instead of facing each other.
この場合、次のような言い方ができます。
ーI feel more relaxed sitting next to my friend rather than across from her.
「友達の向かいに座るより、隣に座った方がもっと落ち着く」
to sit next to ...「…の隣に座る」
to (sit) across from ...「…の向かいに座る」
ーI find it more comfortable sitting side by side with my friend instead of facing each other.
「お互いに向き合うより、友達と並んで座る方がもっと落ち着く」
to sit side by side「並んで座る」
to face each other「お互いに向き合う」
ご参考まで！
I feel better sitting down next to each other rather than across from one another.
"向かい合って座るよりも横に並んで座るほうが落ち着く"
- I feel better sitting down next to each other rather than across from one another.
- I feel more calm sitting next to you over sitting across from you.
- It feels better to have you sit next to me rather than you sit across from me.
カナダ 
アメリカ合衆国 
