Without using Tor, VPN or other methods to hide your identity and to leave no trace for your government, Bitcoin is considered illegal in your country so I don't believe there's any legit way you can do it without getting in trouble.
Bangladesh is known to be against Bitcoin, one of the few countries against it actually. By getting started into Bitcoin in your country, you'll risk
being hunted by the government.
Therefore, one option I could think of (however
I do not condone doing this and this is just a way you can
receive money without anyone finding out) is by using Tor or a VPN to download Electrum and then installing it on an airgapped PC. You can then generate a wallet seed and have a receive address you can safely give others to send you BTC.
However, keep in mind that any little mistake could cost you a big hit from the government. I would really not risk if I was you. If you will post your address somewhere on the Internet (or if you give it through SMS or social media) without hiding your identity and IP, you might get yourself into trouble at any given time. My question is, how will you buy Bitcoin from someone without the gov finding out? One way is by buying through bank on Bisq form another person, but that's just as risky.
EDIT: You can also generate a paper wallet offline. Hell, you can even put all these methods aside, be super paranoid and
create a wallet all by yourself. And there's a way of getting started without buying at all by becoming a valuable member of the forum and joining signature campaigns here. Just make sure your identity is hidden, but again,
I do not condone doing this.