There are two main regular ways to express "time to + "Inf""
- tempus + genitive gerundive. c.f.: Tempus adgrediendi aptissimum visum est (Liv.AUC.10.20.9.1).[Time seems most fitting to attack]. scio fuisse et honestius moriendi tempus et utilius(Cic.Qfr.1.3.6.1) [I know there was a more honorable and useful time to die].
(*) 2. tempus + inf. as suggested: jam tempus agi res (Virgil). [now it is time for things to be done] -- note res here is accusative as part of AcI.
If we are free to to use "to dare" indeed that equates to your second suggestion "Tempus venit audere" or "Tempus venit audendi"
Another, third, option could be to mimic the famous nunc est bibendum with nunc est audendum,
As for if to use venit or advenit. Interesting example popped in Livy: Forte lustrandi exercitus venit tempus, but one version reads advenit instead. I only guess this means both options are very natural. (though other might suggest this piece of information from Livy rather implies the opposite, namly that one option is to be preferred)
As vēnit vs. venit. Usually the English present perfect equates to the Latin perfect. There is also this verse: vēnit summa dies et ineluctabile tempus\ Dardaniae (Verg.A.2.324); but this signifies an end of era. I would vote for vēnit unless context suggests the time really not here just yet.
As for Tempus advenit audacius: audacius is either an adverb comparative (i.e., more boldly), or a neuter adjective comparative. (as oppose to masculine/feminine audacior). So it sounds like time itself is bolder. I guess the the intention was tempus advenit esse audaciores
(*) I am not sure "tempus venit audere" works. pehaps it works only with tempus est. More research needs to be done on this.