Curious how your workplace is handling this as laws here are very different to the US (depending on State). Are you still going to be on payroll as an employee or some type of contractor?

If an employee they need to operate payroll in the UK (called PAYE), and they need to consider if you create a permanent establishment for them. There's also legal and HR requirements on them under UK laws (right to work checks, redundancy laws, can't just fire you, pension auto-enrollment, minimum wage checks, health and wellbeing, safety, minimum holiday pay, sick leave, just to name a few, theres lots more and even more coming in a new law that's just passed).

If you create your own limited company and operate as a contractor, you will likely be "inside ir35" but the workplace needs to assess this themselves. This means your own company will have to operate payroll and keep in line with employment obligations. If this is the direction you're probably better off using an umbrella company but make sure you pick a reputable one with good reviews rather than the cheapest. This could also cause the workplace to have a UK permanent establishment depending on your role but less of a risk. If you DM your job title I could tell you the rough risk.

You could be a self-employed contractor which means you have to submit tax returns yourself and the workplace has no UK presence but it technically risky from a tax / legal point of view.

Once you move, you'll likely become tax resident in the UK so should inform/register with HMRC. You'll need to start paying national insurance after 12 months. You still have to do US returns forever. It's one of the very few countries who do this by the way.

Check out moneysavingexpert.com for everything it tells you about - anything to do with banks, savings, credit cards, insurance, electricity, mobile contracts,, broadband etc). It's a life saver to explain different products to decide what you actually need, and then where is the cheapest or best value.

Buy anything above £100 on a UK credit card but pay it off on the statement day (if a normal one, look for 0% spending cards or balance transfers for essentially a free or cheap loan but might need credit history). This gives you extra putrefaction (called section 75)

Getting a bank account is the hardest bit so hopefully the HSBC account makes it easier but worth getting a UK based one too once you have an address (it's free here so you can easily have more). I think HSBC sucks to be honest.

Getting a place to live can also be tricky. Renting can take some time to find and accept a place (one to three months depending on local availability). Buying can be a long ass process. Start looking on rightmove to get an idea (for renting or buying). I would rent for a while to get to know the places or ask someone locally where to live. You could rent an airbnb for a month (or another form of holiday rental) to make your life easier.

Check if you need a car where you live and if buying, look at autotrader.co.uk for an idea of prices but also look at car insurance as can be expensive but and varies enormously by car model. Look at how long your driving licence will last, if you can transfer or need to take a test after a while (DVLA is our licencing agency).

Once established in a place, register with a GP and dentist asap.

Theres a new rule about traveling to the UK if you have dual citizenship - you have to use your UK passport for the flight to the UK.