Wнιтe said:
You should do some tests, because that would help a lot.
Oh I will, I just don't really have the time to right now.
@OP:
Have Instagram open on your phone.
Sign into an unused account (fresh).
Go to where you can change your username.
Type the one that you wish to swap.
Go to your computer and sign into the IG you wish to swap.
At the same time, spam "Done" on Instagram to try claiming the IG that you're swapping, whilst changing it on your desktop.
I've done this more than once and pretty recently and I have yet to be turbo'd, and I don't think Instagram has cool down/timeouts on mobile.