Hi,
There is no different if you break it down into smaller chunks, "per se". If you are triggering this flow 10000 times it isn't going to matter if you do 2k chunks or 45 at a time, it won't work.
You should make sure this flow has Concurrence turned on for the trigger and set to 1, so no more than 1 copy at a time can be running.
It's also impossible to tell you what impact. If you are a customer that has 3 flows, this is one and the others fire 1 time every 10 years.. is not the same as finding out someone has 10 of these types of flows and 300 others all working at the same time.
There is no "safe" threshold for pagination as it relates to performance. it takes understanding the entire environment ecosystem.
For me I do not like to do 100K at a time. I want to get as many done in smaller batches 10-20K so that I can more readily see and gauge performance and timing.
I would make it configurable as an Environment Variable. then run some tests for yourself. This way you can test, without redeploying each time you change the pagination size.
