Oppo, Mi, Vivo, Realme.
Realme is from different.
But Samsung is still better but little expensive.
And none of the above were Indian company.
First of all, Realme is a brand owned by OPPO. Oppo, Vivo and OnePlus have same parent company i.e. BBK Electronics.
Xiaomi or what we like to call MI is a completely different company.
I'd strongly suggest you buy OnePlus phones if the budget suits you, been using it for 1 year and have had "Zero" issues. If the budget doesn't allow you to go for high-end flagships, then Realme's phones are solid ones in the budget. If you aren't a fan of ColorOS, then go for Redmi Note 7 pro (or K20 pro)
If you aren't a fan of MiUI either, ASUS Zenfone should be the best choice.
Goodluck! Happy Diwali