More new rules for 2021:

10.1.4 SPECIAL STAGE OVERLAP
The choice and timing of the special stages must be such that
there is no overlap of at least the first 15 cars on any special
stage before the start of the next special stage at normal
intervals.
10.1.5 NUMBER OF SPECIAL STAGES BETWEEN SERVICES
The construction of any itinerary that contains any more than
4 special stages (under the exclusion of a super special stage,
if any) between two services is subject to FIA and WRC
Promoter’s written approval.
The latter probably is the reason why Rally Finland cannot run their 2020 route in 2021. They would have run 7 stages on the Friday afternoon.