It might be a real chore to roll forward everything that is possible to roll forward, and it might not even be advisable.

But at the very least:

(a) the main Form 5471 should roll forward so it is at least present in the subsequent year (currently on transferring there is zero evidence in the 2020 software that there was a Form 5471 in the prior year return)

(b) the great majority of the data entered on Form 5471 pages 1 and 2 will be the same from year to year and should roll forward

(c) the ending balance sheet data for the prior year should roll into the beginning balance sheet in the subsequent year (Form 5471 page 4, Schedule F, Balance Sheet)

(d) it would be a bonus if the ending values in prior year rolled to starting values in subsequent year for Schedules J and P.