I agree with what pooya87 wrote, and since OP already has 0.4 BTC, it might be better to keep investing in it than to start experimenting with some altcoins - because their price always depends on the price of BTC.
We got into crypto in order to help us own a house and be able to be semi-retired within the next 10 years, if that helps.
It's a long-term investment, and you should realize that you take a big risk if you put all your savings in the same basket - no one can know what will happen to BTC in the future. In addition to that risk, you have extra worries about how to secure your digital assets - and be sure not to choose a custodial solution or anything online where you don't have 100% control over your private keys. Not only do you invest in a very volatile asset, but you have to learn how to be your own bank - preferably one that has the highest security standards.