Output: SetAsync request dropped. Request was throttled, but throttled request queue was full.
and also it says 'try sending fewer requests'.
What does it mean by try sending fewer requests and does it effect anything if the request was throlled? will it not save the data?
When sending data store requests, you're taking up network space of the external data base that Roblox uses. To prevent too much space being taken up, the data base enforces limits on their API that ensure one entity isn't sending too many requests and taking up all the network space for itself. This is known as rate limiting.
Roblox allows developers a certain budget of requests that can be made in a certain amount of time to comply with its data base's rate limits. When you send too many requests, your requests throttle. This means that they are not sent to the data base for a certain amount of time, but they will be sent eventually. Throttled requests queue up, sending one by one. If too many throttled requests queue up, and the queue becomes full, Roblox will simply begin ignoring your requests. This is what's happening here.
To fix your issue, you need to try sending fewer requests, as the output instructs. Here is a link that includes the budget that developers are given when working with data stores. It also describes some errors that you may run into.
I hope that this helped!