Is it a good idea to in invest in ETH now? I read somewhere its going to get merged with Eth V2 in 2022 (Docking) and most people won't be able to mine further as it requires a 32 ETH stake .
Depends upon how much you are planning to. If you are bit hesitant, I'd recommend a monthly sip of your target amount.
Yes, mining ETH will be impossible after Eth 2.0 but the value of Eth may still increase thereafter as the transactions under Eth network will be faster and may charge lower fees due to POS.
Imo, Vitalik is trying to make eth the default cc payment option. I am very positive about Eth's growth in next 5 years. It may even be another BTC in making or even replace it. Not to say, this is my personal opinion and you should dyor.