My pleasure.

Thank you for your answers 😊 they really helped.

"食い入る" usually just means "bite into something" or "eat into something". It does NOT mean "gaze into something" or "stare at something" all by itself. ／If you mean so in your sentence, you should use "食い入る" with another verb "見る" and say "食い入るように見る", which means "gaze into something as if you were biting into it". Otherwise, you could just say "じっと見る", which might be much weaker than "食い入るように見る".

"じっと" usually means "still". If you say "じっとする", it means "stay still". ／If you say "じっと見ている", however, it means "look at something without turning your eyes away from it". It does NOT mean "still" here in this case.

A native speaker would say "そう考えて、ただ展示物を〔じっと〕食い入るように見ていた気がする｡" or something like that.