Images under review for several months

I think this process will now take about 100 to 120 days.

Its my prediction not from any adobe stocks persons.

I am waiting for 4 months now. I had images that were pending in review section for 5-6 months. 

Maybe your 50 assets were submitted in the wrong category. It may also be that a moderator got assigned your newer submissions. For me, this is a glitch in the moderation process.

If you want to test: submit the first asset in your waiting queue again. See what asset get moderated and delete the other one. I would not do that on a massive scale, but as a test, with one image, that should not do harm to your account (spamming gets your account banned!).

Review times vary based on type of asset and how many other assets are ahead of yours in the wait queue.

On average, Photos & Vector Graphics are reviewed in 5 -15 business days.
Illustrations & Generative AI could take 1 -3 months due to an immense backlog of AI submissions.

There's no way to know when Adobe Moderators will get around to reviewing those older images, and there are sporadic reports here in the Forum that not all moderation is done on a "first in / first out" basis, which you've discovered. You didn't mention how many of the 2.5 month old images remain to be reviewed, but if I were you, I would try deleting just a handful, maybe 4 or 5, and reupload them to see if those catch the attention of the Moderators.