Zotero has supported adding items via arXiv ID since 2018, and saving from arXiv.org since forever. There's not currently a dedicated field for arXiv IDs, but t

Zotero has supported adding items via arXiv ID since 2018, and saving from arXiv.org since forever. There's not currently a dedicated field for arXiv IDs, but they're added to the Extra field and included in exports (and accessible however you want via Better BibTeX export). (Disclosure: Zotero dev)