ACL conference papers usually cap the main body at 8 pages, with unlimited appendices. KDD has a hard limit of 9 pages plus 3 for references and appendices.
look at essentially any proceedings of any conference (in crypto we dont really do journals). see EUROCRYPT for example https://link.springer.com/book/10.1007/978-3-031-91098-2 in there, every paper will be cut down and referring to full version for proofs etc. which are typically on eprint.iacr.org
We usually do conferences in cryptography/security, and most of them have page limits: CCS, USENIX, NDSS, S&P, CRYPTO, EUROCRYPT all have page limits (some allow appendices, which reviewers are not obligated to read).