Did it for six years while working full-time.

Smallest bag you can get away with. I used a 28L North Face Surge II. The difference between a regular decent-quality backpack and an expensive "digital nomad" bag is mainly in how much they cost.

Clothes that don't smell bad and can wash and dry overnight in a hotel room/Airbnb/hostel: Ex Officio underwear, Icebreaker or other merino wool t-shirts. Avoid jeans (heavy, take forever to dry) and anything made from cotton. Choose neutral colors and a few items you easily mix & match, you don't want to carry a lot of clothing. Remember you can buy clothes pretty much everywhere. Pro tip: hotel shampoo will work for washing clothes in a sink or bathtub.

A phone with two SIM slots is handy. I used Google Fi for US service and the second slot for a local SIM anywhere I stayed for more than a week. iPhones have a virtual SIM and a SIM slot (maybe not every model).

I ended up traveling with a Chromebook because everything in the cloud and cheap. Laptops get stolen, lost, or broken and getting repairs overseas can present major problems, depending on where you go. Acer Spin series are better than the ultra-cheap models targeted at students.

Chargers and cables are usually easy to find but take quality versions of the cables/chargers you need. You probably don't need an AC adapter, hotels usually have them or buy locally, but a small universal adapter might come in handy. Make sure all electrical items (laptop and phone charger, electric razor) are 110/220v compatible. Don't take hair dryer, curling iron, etc.

Unless you go to very remote/undeveloped places you won't need things like a water purifier (bottled water is ubiquitous), elaborate first aid kit, tent, etc. Nomading is not camping.

Written prescriptions for any meds you need. Be aware of local drug laws, i.e. absolutely no Adderall or amphetamines in Thailand. Antibiotics and other common medicines available pretty much everywhere.

The biggest hassles I've seen nomads bring on themselves have to do with money and communication. Keep your US/local bank account and credit cards. Set up paperless (online) billing and autopay for any bills. Get a Schwab Investor checking account, they refund all ATM fees, and those can add up (plus Schwab has great customer service 24/7). Get two debit cards and at least two credit cards and keep them separate -- one in the wallet, one in the backpack or locked somewhere safe. Arrange for mail forwarding back home. I used Traveling Mailbox (US only), they scan your mail and put it online, they will even forward, receive packages, and deposit checks.

Take good photos of your passport and other documents, keep them in cloud storage and on your phone. Know what you will need to get your passport replaced because that can turn into a major hassle overseas.

US citizens: You still have to file and pay taxes. Anyone telling you otherwise is wrong. If you live out of the US for 330+ days out of a year you may qualify for the FEIE, a potentially big tax break. Non-US citizens should check on their tax obligations, it can get complicated with residency rules.

Local medical insurance probably not accepted outside your home country. CIGNA and other companies offer expat policies. Routine medical care is almost always cheaper than in the US but insurance is a good idea. Read reviews because some companies selling travel/nomad insurance don't like to pay claims.

Carefully check visa and entry requirements in advance on official government web sites, and then check again. You can get refused boarding the plane or entry for seemingly small mistakes. Looking clean and groomed helps get through immigration, you want to look like a tourist, not a backpacker or someone who will be trying to get a local job. Reason for visit is always "tourism," never tell immigration authorities you plan to work in their country unless you have a visa that allows work.

Don't overthink it and stress too much about equipment and all that. Take the bare minimum, like what you would need for a long weekend at a hotel or friend's house. You have to carry all that stuff. Mostly you won't need half of what you think you will need. Think hard before buying expensive nomad gear.

Enjoy!