A risk of illegally obtained benzos is they may not be actually that medication. Many "pressed" bars for things like Xanax in particular are other benzos similar to it but not actually it and may use an even cheaper medication or lots of fillers. Dosing would be unreliable and difficult, or potentially risky.
To obtain legally, PCP/GPs will prescribe them short term for anxiety, sleep, panic attacks. Then eventually may refer you to a psych doc for med management if you need or want them longer than a short term use. You can use the search feature here to find similar threads about it.
If you want to add benzos to your protocol (such as maybe for SN), it is probably better to acquire them legally than from DNM or a dealer where the quality cannot be guaranteed. If you are using them that sort term (again like for SN protocol where you take them when you drink SN) then the concern of getting hooked on them as another user pointed out is just not going to happen, someone would be hopefully dead from the SN. And even then, a one-time use like that isn't going to cause someone to be just immediately addicted to them. Yes, long term benzo use does cause mental and physical dependence issues though.
If you are just wanting to them not for a protocol to help with something like anxiety or panic issues, just go to a doctor and legally obtain them and consider the risk of them becoming habit forming and remember they require reduction over time when you do want to get off of them. But plenty of people take benzos to help with this and have also very safely gotten off of them.
With whatever you decide, I hope you find peace & serenity.