Business Interest Expense Carryforward on Form 8990

[Tal10]

Hello. I have a client who is a real estate professional. He only deals in residential rental properties. He has been subject to 163(j) since inception. He did not make an RPTB (Real Property Trade or Business) election from 2018-2021, as he gained more benefit from the depreciation deductions than he would have from the interest deductions. This changed in 2022, however, with the more restrictive limitations in place. So, an RPTB election was made for 2022. But now there are several million in disallowed business interest expense carryforwards, and I cannot, for the life of me, find information on how I should be completing Form 8990. Has anyone run into this, and if so, what resources did you use to muddle through this form?