What are best practices wrt realizing gains if you are planning to exit PR?

If someone decides they will be leaving BFR-PR (and disqualifying themselves from Act 22/60 individual investor decree) in the future, it would behoove them to realize all gains possible prior to exit, to enjoy the tax benefits while they have them. What are some best practices wrt realization of gains prior to leaving? Some specific sub-Qs:

  • How to realize gains on assets that you cannot easily sell (e.g. equity in private companies, VC fund interests, etc)?
  • If you bought assets while BFR-PR that are now underwater, if you avoid realizing the loss prior to exit, then can you subsequently realize the full lose, offsetable against income according to the usual rules wrt US federal taxation?
  • How is PR real estate taxed if you sold before exit vs after exit?