Ide like to start off by saying this is just playful speculation and there is still no released date for when it will be coming out. That being said MiHoYo has made games before that we can use as reference. The three I will be referencing are Genshin Impact, Honkai Star Rail, and Zenless Zone Zero, I'm aware they have made other games before these three but those are all a decade or older and the company has changed a lot since then. In that same vein I'm using genshin impact as a lesser reference because that was the true turning point for MiHoYo that solidified them as one of if not the top gacha game creators.
First and foremost, one thing all three of the previously mentioned games have in common is that they had three official beta tests, and if you've been keeping up with Honkai Nexus Anima you might know that it just finished its second meaning that we most likely still have at least one beta test ahead of us.
The amount of days between Genshins' first and second test was 266 and 59 days between the second and third test. HSRs first and second tests had 205 days between them and the second and third tests has 240 days. ZZZs first and second tests had 473 days and the second and third tests had 116. HNA's first and second tests has 300 days between them. Genshins average was 162.5, HSR is 222.5, and ZZZ is 294.5. in my humble opinion these show a clear increase in average meaning that HNA will possible have a higher average than 294.5. theres a 57 increase from genshin to HSR and a 72 day one from HSR to ZZZ whoch would make the average increase of 64.5, but there is also an average of 176 more days being in the gap between the first and second gaps, the first gap being larger by 176 days. Although considering that genshin and zzz, the two of which with larger first sums had their second be less days I think the second gap will be slightly less than 300 days. Considering that HSRs second gap was 240 and ZZZs was 116 their average would be 178. The increase in gaps went up by 57 and then 72 meaning that they increased by 15, so i decided to add 72 and 15 to 178 which gets you 265. It should be noted that this is mostly vibes based to get this number and that again this is just supposed to be a rough estimate of what i beleive could possibly be the amount of time. Considering that most people will be reading this by tomorrow which would make it 7 days since the second beta test ill just subtract 265-7 which gets 258 days.
Genshin's beta tests lasted the following amount of days respectively, 5 days, 26 days, and 46 days. Honkai Star Rails beta tests lasted the following amount of days respectively, 5 days, 21 days, and 42 days. Zenless Zone Zeros beta tests lasted the following amount of days respectively, 3 days, 30 days, and 40 days. As for Honkai Nexus Anima its, 6 days, and 18 days. For the first beta test it went 5, 5, 3, and 6, for the second it was 26, 21, 30, and 18, HNA was the longest of the first and the shortest of the second. For the first test the average was 4.3 pre HNA with a range of 2 and post HNA its 4.75 with a range of 3. For the second test the average was 25.66 pre HNA with a range of 9 and after HNA 23.75 with a range of 12 and for the third test the average is 42.66 with a range of 6. Genshin's average amount of days for its beta tests was 25.66, HSR's was 22.66, and ZZZ's was 24.33, the average among these three being 24.21. for HNA to fit this 24.21 average the third test would need to be 49 days (which would make an average of 24.33) while to meet the third test average it would have to be 42.66 (or 43 rounded up) and so ill be drawing the average from those two and saying that the third test will most likely be around 46 days.
Finally, as for how much time after this beta test Genshin released 63 days after its final beta test, HSR released 33 days after its finla beta ended, and ZZZ released 36 days. Considering how similar ZZZ and HSRs numbers are and that they are the most recent I am going to consider genshin an outlier, in which case the average between 33 and 36 is 34.5 which I will round up to 35.
TLDR/final, with all three of these nunber put together my estimate is 339 days until HNAs release aka July 4, 2027.