It's painful that I'm just knowing about this forum when I've been using crypto since 2019 but thanks to a friend AJ for telling me what I'm actually missing so far, I have few questions as a new forum user I hope I get the best answers.
Wow, welcome to the forum mate, and do say some thank you to your friend, he's a true friend indeed.
1. I've been using wallet called coinbase but my friend keep saying it's bad for my assets what do you think?
Yes, coinbase is not the best place to store your investments because it's a centralized wallet, this means you don't actually own the assets in your coinbase wallet but the company(coinbase) does, and why is this? It's because your don't own the private keys to your coinbase wallet, the company(coinbase) does, and remember the golden rule in crypto, "NOT YOUR KEYS, NOT YOUR CRYPTO", this means that if you don't own the private keys or phrase of a wallet, then you dont own the crypto in that wallet.
You need a decentralized wallet like trust wallet or metamask, this wallets let's you own your private keys or phrase as well as your crypto full time, they are the best wallets to store your crypto investments.
2. If I want to keep my assets in a stable coin which one is the best? he said DAI but I'm not sure as all I see online is USDT.
YES, if you ever want to store your asset on a stable coin, DAI is the best choice though USDT is older and more popular, the thing is, TETHER is a centralized company and as such, they have access to freeze any bodies USDT right in their(your) wallet, but according to research, DAI is a Decentralized stable coin and as such, it doesnt have such access.
3. Recovery seed can be written on paper but I'm still not having a full confidence about this because I'm living with my siblings, not saying I don't trust them but I want something more secured, how do you guys keep your keys safer?.
The thing is, alot of people will say alot of things, tell you how to and how not to store your seed phrases or private keys, but the truth remains that you still have to do that which is best for you, people live in different places and in different conditions, what works for the other person might not work for the next person, so you have to look for that which will work for you.
For example, alot of people condemn or do not recommend storing private keys or phrases in a cloud storage(online), but I have all my seed phrases and private keys stored in an online cloud storage since 2015, and I've never had any issues, all you need is choose the right app, and you are good to go, I have access to all my private keys and phrases any time and any where I go, whether with internet access or not, whether with my phone or laptop computer.