Curiously, I had no nausea problems while taking aerobatics training in a Citabria nor while flying normally. But there’s something about being still while eyes are seeing apparent motion. The incongruity goes right to my stomach. I loved extreme roller coasters but couldn’t handle “motion on a screen” type rides.
Also, on the subject of hardware to run MS2020 (or 2024), you might want to spend some quality time on topical technical forums. The increase in performance isn’t always linear with increasing cost or capability of hardware components. You will see users of even top-end hardware complaining about performance problems. I believe that optimizing the simulator is equally important to choice of hardware.
This is not the main FS2020 forum but I had it in my bookmarks:
https://premiumbuilds.com/features/microsoft-flight-simulator-2020-performance-benchmark-analysis/
Currently, I am running MSFS2020 on a Ryzen 5 2500u laptop with 16GB of RAM without a separate GPU. This does not meet the minimum requirements. It took a lot of tweaking and troubleshooting to just keep it from crashing. But now I am getting very good results at 1600x900 resolution at about 20 fps which is actually fine for me.
I am looking forward to getting a more powerful computer.
I have been prone to motion sickness in the past in certain situations. For me after a certain amount of time I have always gotten past this and have few problems after that. I already had hundreds of hours in hang gliders and ultralight aircraft before I went after my private pilots license. The winter and spring that I took lessons had a lot of bad weather... so much so that they always joked that they didn’t think the weather was bad enough for me when I showed up to rent a plane. But despite my previous experience I still got queasy quite a few times when we were got bounced around.
What type of aerobatic training did you take in the Citabria? I have never flown one, but I have time in Aeronca Champs and Chiefs. We belonged to an ultralight club which evolved into an experimental club, which eventually evolved into a vintage aircraft club.