P.S: I had tried downloading all the blocks at least 10+ times but lost it every time to the power cuts.
You need a laptop instead of a pi. It probably depends on where you live, but here second hand laptops can be pretty cheap.
I guess the reason you are suggesting for a laptop is because of higher CPU processing power and you are right there.
I spent some time on understanding on how the bitcoin core syncs the blocks and then I found out that the speed depends on CPU, HDD/SSD and RAM.
While the frequent power cuts were a major issue in my scenario, it has slightly decreased now.
Since I also have a laptop (AMD Ryzen 5, 8 GB RAM) and a desktop (AMD Ryzen 5, 16 GB RAM), I tried running bitcoin core on both of them and the desktop was obviously better.
The main bottleneck in my system setup is that I am using a HDD for storing block data.
The read/write is not that great and so the disk utilization is always at 100% which is why the blocks are downloading slowly.
I have somehow managed to reach 86% of the sync process and now syncing has become even more slower.
The reason is because of the huge number of transactions included in every block in the recent years.
Hopefully, if everything goes right, I might be able to sync all the blocks in about a week.