2004-2014, Congress was in power and the country saw a lot many scams during that time period. Yes, the Congress had the numbers back and instituted dubious characters as governors of states. This did take the advantage away from the BJP in a couple of states. The Modi change was necessary back then. The BJP would still have come to power in 2014- Modi or no Modi.
2019- As Bevab pointed out, Modi did exactly what he promised and delivered on the manifesto. The Saffron wave was strong and they roared back to power. Also was helped on the way by stupid statements by Rahul Gandhi.
2024- I get why you might feel this way. The BJP has tried to create a Hindu centric nation and this does attribute to a lot of tensions among people. Now, I am not against the concept of a Hindu nation, however, those in power need to understand that the existence of a Hindu nation doesn't belittle other religions. Forget other religions, those propagating 'Hindu nation ideologies' arent aware of the Hindu' ways themselves. This is what creates a concern.
Hinduism has been a way of life. Unlike Islam, no one is asking you to pray 5 times a day. One can pray the way they want. The BJP elements at the center have been trying to control a culturally diverse nation. Remember the ITC advertisement in Kolkata? The one where it was depicted that Ma Durga was eating mutton? It is normal in West Bengal to offer non-veg to the Gods. It is also normal in some parts of Maharashtra. If the 2 bald guys haven't seen it, doesn't mean that it cannot exist.
As for a change in 2029- I doubt it, the country doesn't have a proper opposition. The Congress has been putting their faith behind Rahul for the last 15 years and it has yielded no fruit. They need to realign and start working for the betterment of the people, if they are to expect anything. I had high hopes from the current Karnataka govt, but they are embroiled in various inter Congress fights themselves. It wont work this way. Either the Congress works OR the BJP screws up. Chances of both happening are minimal, but either needs to happen for the Congress to return to power.