Professional help regarding eventual exit tax

My spouse is Japanese and I'm American. We are thinking of moving to Japan for a while for our child's education and upbringing, but it may not be a permanent move.

A bit about our finances:

– Our finances are shared
– All of our assets are in the US. All of our unrealized capital gains were earned in the US thus far, over 20+ years. There is enough there for the exit tax to be expensive
– Enough of our gains and are in taxable accounts that I don't want to realize them now to reset the tax basis

I may be able to come under a Type 1 visa for a few years, but she would come as a citizen

We don't mind paying the exit tax on capital gains earned while in Japan, but paying them on the two decades before moving there would be problematic.

I'm giving all this context not to look for a solution in this thread, but rather to ask for any recommendations on reputable tax advisors who may be familiar with the laws of both countries and can help us plan the move so we don't have a bad surprise a few years down the line.

Thank you in advance!

by iatnup