The translation is What I felt is by having read this manga... このマンガを読んで→このマンガを読んだことによって

I read this manga and felt xxxx

(私が)このマンガを読んで感じたことだけど 私 is the subject of this sentence, 私 is omitted. 感じたこと = what I feel/felt このマンガを読んで感じたこと the thing what I felt, when I read this マンガ だけど = Informal conjunction or adverb meaning: but, however, though, still, nevertheless 私 has a negative opinion on the マンガ, then 私 is using だけど in this case. Here are other examples with て感じたこと 聞いて感じたこと the thing what someone felt, when the person heard something 見て感じたこと the thing what someone felt, when the person something 触れて感じたこと the thing what someone felt, when the person touched　something Here are examples with て感じる （人）が人間として感じる心の痛み emotional pain of someone's life as a person 物事に対して感じる心 a feeling toward something 長い道を歩いて感じる辛さ a feeling of pain while walking a long way

> "このマンガを読んで感じたことだけど. I think It means "I read this manga and I had a feeling/an impression that ...... (continues)" "Having read this manga, I had a feeling/an impression that ...... (continues)" The speaker does not mention whether they are moved or not. > "このマンガを読んで感じたことだけど. (この)(マンガ - を)(読ん - で) ＋ (感じ - た)(こと) ＋ (だ - けど). A literal translation to show the structure would be. "The things which, having read this manga, I felt is that ...." **** This sentence is not completed, it continues like: 「このマンガを読んで感じたことだけど、まず絵がすごいよね、そしてストーリーも独特だ。ちょっとほかにない作品だと思う」 * が／だけど shows "the reservation of conclusion (= I haven't said everything yet)".

yes, basically! you’ve got it!