I recently bought a Slim. I chose the Slim because there isn’t a significant improvement with the Pro over the Slim. Yes, you might get slightly better FPS, but that’s about it. Unless you have a 4K 53-inch TV, the Pro isn’t really worth the extra cost. On top of that, you have to buy the disc drive separately for the Pro, while you can find the Slim disc version starting around 160k.
As for games, the PS Store has discounts every month, and you can use a price tracker to monitor sale prices. If you’re using a PS5 in Sri Lanka, create an account in the Indian region (PS5 region and PSN region are different, and the PS5 region itself doesn’t matter). You can then buy games directly using a ComBank credit card—no need to purchase overpriced gift cards.
The local used game market is expensive (like most used items in Sri Lanka), so if you have an unlimited internet connection, you’re better off buying games during sales. I managed to get many AAA titles from PS Store sales over the last two months for about 20% of what they would have cost in the local used market. Also, make sure to get a 1200VA UPS. Sorry for replying in English but typing in Sinhala takes too much time.