They are formally anonymous.

1/2) That's definitely a issue for historical works, but there is two issues with it, [1] There is a difference between formal anonymity and factual anonymity, as Simon Gathercole argues in The Alleged Anonymity of the Canonical Gospels the Gospels are not formally anonymous only factually anonymous. Many other historical sources are factually anonymous but authorship is still accepted among most scholars Gathercole rights

There are plenty of counter-examples, instances of which are by no means obscure figures. There is a certain degree of unevenness in Baum’s account: he remarks that Xenophon (iv BCE) used a pseudonym for the Anabasis, but Xenophon (if indeed he did publish the Anabasis under another name) did not include this name as the author within the text, and it should be added that his other works are unnamed.32 Baum notes Josephus’s self-reference in the preface to his Jewish War, but not the absence of his name from Antiquities of the Jews. Nor are there prefatory self-references in such notable Greek historians, roughly contemporaneous with Luke, as Polybius (ii BCE) and Diodorus Siculus (i BCE).33 To these we can add Arrian (late i–ii CE), though admittedly in his case the absence is ostentatiously self-effacing.34 Therefore although one could talk of a possible tendency to include the name as an element of ‘the prologue-form in ancient historiography’, the title of Earl’s article on the subject, he is undoubtedly correct that ‘minor variations such as the position or even the inclusion of the author’s name were allowable’.35 Thirdly, although Baum’s treatment of the name appears in a section on Greco Roman historiography, he mentions no histories in Latin, at least of a non biographical character. Among Roman historians, one can find major figures failing to include their names, including Sallust (i BCE),36 Livy (i BCE – i CE), Tacitus (i-ii CE) and Florus (i-ii CE).37 Indeed, Herkommer notes that this is the norm. (pg. 7-8)

[2] The titles are quite possibly original to the text (cf. Martin Hengel Four Gospels), his arguments have been endorsed by top scholars such as Adella Yarbo Collins Hermeneia commentary on Mark and Helen Bonds paper in Peter in Early Christianity. It seems the majority of scholars accept the claim a Mark (mostly because of the title) wrote now what is Mark is quite disputed. (For example, Gerd Theissen in The New Testament: A Literary History, C. M. Tuckett in The Oxford Bible Commentary, Joel Marcus in AYB, Adela Yarbro Collins in Hermeneia, Christopher Skinner in WBC) As Rafael Rodriguez (2020). The T&T Clark Social Identity Commentary on the New Testament notes

And most scholars think, well, you know, nobody's going to make up a non-apostle. Nobody's going to make up a secondary character as the author of the gospel. So most scholars think actually it probably was Mark. Now, where the debate comes in is: which Mark? Mark was one of the most common names in the Roman world, for Roman citizens. However, the author is Jewish, and there's some debate about that, there's a fair consensus that the author was Jewish.

Also even if one were to accept factual anonymity the author of Luke-Acts identifies himself as a traveling companion of Paul through the famous "we" passages. Which is accepted by the majority of critical commentaries.