I filed late this year because I had a lot going on and wasn’t able to do it early because of different circumstances. I finally filed on 4/26 I believe, but it’s not showing up on the transcripts yet as even being in their system but it’s showing up as received on WMR. I filed electronically and included the IS with it.
Interestingly enough, I filed an amended return for 2020 and that’s already showing on my 2020 transcript lol – I filed that electronically as well.