楽しんでた

was enjoying, was having fun

→ 楽しむ
楽しん enjoy + Te-form (conjunctive) + Past tense
verb · imperfect indicative Rare #39,991
was enjoying, was having fun Colloquial contraction of 楽しんでいた.
JA: 昨日、友達と映画を楽しんでた。
EN: I was enjoying a movie with my friends yesterday.
Conjugation of 楽しむ
Indicative imperfect
楽しんでた

みんな楽しんでた

Everyone was having fun.

仕事中自分の音楽を楽しんでた

I enjoyed listening to my own music while I worked.

— 落下の解剖学 (2023)

彼はいつのように楽しんでた

He was having fun as usual.

— 海の上のピアニスト (1998)