が多くて

there are many, and

→ が
phrase Rare #22,140
there are many, and Often gives a reason or background for what follows; it can also trail off when the speaker leaves the consequence unsaid.
JA: 宿題が多くて、今日は出かけられません。
EN: I have a lot of homework, so I can't go out today.

結構人が多くて結構賑やかだ。

There are quite a lot of people, and it's pretty lively.

来たいという奴が多くて大変だったよ

There were so many people who wanted to come that it was a real hassle.

— フィールド・オブ・ドリームス (1989)

まったく、宿題が多くていやになるよ。

Ugh, I hate having so much homework.

「今日はどうだった?」「お客さんが多くてめっちゃ忙しかった」

“How was today?” “We had a ton of customers, so it was really busy.”

いろいろ注文が多くてうるさかったでしょう。

I’m sure I was a pain with all my demands.

最近は注文が多くてね

I've been getting a lot of orders lately.

— 戦争と女の顔 (2019)

この本は漢字が多くて難しいです。

This book is difficult because it contains a lot of kanji.

“ブルーマジック”について仕事をなくした売人が多くて

A lot of dealers have lost their jobs over “blue magic.”

— アメリカン・ギャングスター (2007)

授業と研究もあってやることが多くて…

With classes and research too, I have so much to do...

— ビッグ・シック ぼくたちの大いなる目ざめ (2017)

やることが多くて

I have so much to do.

— オープン・ユア・アイズ (1997)