The phrase "allegedly necessary" is correct and usable in written English.
It can be used when discussing something that is claimed to be essential or required, but there is doubt or uncertainty about that claim.
Example: "The new regulations are allegedly necessary to ensure public safety, but many experts disagree."
Alternatives: "reportedly essential" or "supposedly required".
A fourth kind of response is to embrace the (allegedly) necessary vagueness of the gene concept(s) and to examine why use of the term gene is so useful.
In this case any allegedly necessary competing clause — for example, "a, b, c etc., are the only things" (that is, Tractarian objects) — would just be a nonsense-string produced in the misfired attempt to put into words something that is shown by the fact that when analysis bottoms out it yields as names only such as figure in the conjunction "Ga & Gb & Gc…" (cf. Tractatus 4.1272).
In theology the existence of free will must be reconciled with God's omniscience and goodness (in allowing people to choose badly) and with divine grace, which allegedly is necessary for any meritorious act.
Allegedly, ISDS is necessary in order to increase foreign investment.
Fodor (1998) countered this objection by reinterpreting allegedly semantic relations as metaphysically necessary connections among extensions of words.
Without sufficient information to order the necessary search warrant, the officers allegedly falsified their documents to expedite the process.
Payne allegedly told him he "should use any means necessary [to remove Ward]... including death".
Tieben allegedly violated land-use regulations and failed to gain the necessary approval from Beijing for its investment.
The tactics allegedly include undermining official standards bodies, and suborning big IT companies if necessary, by infiltrating them.
But security experts quickly pointed out that Meitu, which is free to download in Google Play and the App Store, requires way more data from users' phones than is necessary for a simple photo app and contains some allegedly sketchy code.
We spoke to Anabel earlier this year after another discovery led to the Mexican chief of police allegedly instructing his men to make her disappear by any means necessary.
