drop partition update indexes

Dears

i have database RAC 2 nodes 19.3 on linux 7

i have a table that is partitioned on monthly basis, it contains data for almost 3 years and i want to drop the old partitions (older than 1 year)

the storage of the table is almost 250GB and the indexes are of almost the same size

i will be using alter table transaction_log drop partitions x,y,z... update indexes;

are there any considerations/ impacts on the database during this huge drop of partitions,

recently i faced an issue when doing this on other environment that when running the daily maintenance windows it consumes a lot of CPU but i could not fine a link between both activities.