Finances for a Dual Citizen

I'm soon to get my UK citizenship after six years in the UK, and I'm now turning my attention more to my finances. I've reviewed old threads here and seen several recommendations for Tanager for financial advice, but not sure if I'll need advice from other specialists (e.g. tax advisor). The thing is I don't have a lot of £ to be wasting on a financial advisor/tax specialist. I just want to make sure I'm making wise investment choices so I can retire one day, and as I don't know if I'll stay permanently in the UK or go back to the US I need to plan in a way that will allow for both options. I'm also saving up to get a house and am navigating that whole minefield. As I do all of these things, I'm trying to stay straight with the IRS and HMRC. I've been filing myself and so far things have been fine, but I'm always afraid I'm doing something wrong. I think I posted before years back about my woes with Vanguard, who won't let me transition my legacy (mutual fund) account to a brokerage account, and this has really limited how I can invest my money in the US.

Anyhow, can I get more of an idea of the best approach for my situation and an idea of the costs to hire a specialist advisor? I know everyone's situation is different, but in emailing some financial advisors I got one quote of £2000 and that just seems insanely high. I'd be pretty happy with an advisor just steering me in the right direction for investments, and then maybe separately a tax advisor helping file US taxes if they were reasonable. So far FBAR and Self Assessments are straightforward so I don't see myself paying for that service.

The thing to remember about investing in the UK is that unless your investments are in a pension plan, either personal like a SIPP, or in an employer pension scheme then you should avoid pooled investments such as stocks and shares ISAs as they will be taxed punitively by the IRS as Passive Foreign Investment Companies (PFIC). Interest bearing accounts such as NS&I income bonds are fine, the IRS will tax them like regular income.

I went to see a Financial Advisor about a Retirement Pension. As soon as they found out about me being a U.S. Citizen, I was shown the door! Apparently their insurance won't cover advice to non U.K tax residents. Unless you have wealth and can afford the annual fee, keep things simple, that's my advice.