No backup found on this account issue

I by mistake deleted the local backup of whatsapp but my google drive is showing i still have the latest backup which is of 24 feb ,2024.but the problem is when i reinstall whatsapp and press restore from drive its shows 'no backup found ' on this account.im really scared please help me out guys.

Backstory:

I think this might be the cause of this issue but I'm not sure. So 5-6 months before I using a single whatsapp in a redmi note 9 pro and was using a phone no(let's call it sim 1) which was the original no linked to the account but after that I went to college so i bought new phone no(let's call it sim 2) . So I have given sim 1 to my mom and kept sim 2 with me and is using the same account and 2 whatsapp(original one and whatsapp with new phone no).so i think it's a logical problem as whatsapp or Google drive maybe have problem in authentication.

Case 1 (trying to restore with sim 1): Whatsapp or drive might be having problem in authentication because when the latest backup(i.e. 24 feb) was created in my phone it was the different phone no.(i.e. sim 2)Although I'm still using same account and phone. Case 2 ( trying restore with sim 2): Whatsapp or drive might be having problem in authentication because the original no. linked to the original account and phone . So it might be thinking this not phone no linked with this phone or account.

I have tried whatsapp support but they are of no use with their shitty bot replies . They are not helping me in any way

I have a seen a same issue in this sub but case was different.so he just a bought a new phone but had the same issue.

So I think if we can find root cause of this issue then we can find a conclusion that can we solve this issue or not .so can this issue be related to API,or how whatsapp detects backup(maybe not able to detect it in drive) or it just due to glitches which we can solve by trying different trouble shooting methods which might work.

please help me guys data is important than my dear life.