1. Im exempted from T1135 for 1st year but I'm not sure if 2020 or 2021 is my first year
Why do you think 2020 was not your first year?
2. So the deemed disposal date/valuation date must be the date I landed, no matter if I were tax resident or not for 2020?
I think you are a tax resident since 2020
But I can be wrong. If 2020 is not your first year, then when was the first time you landed in Canada?
3. Is it a bad idea to fill out NR74 and asked CRA opinion if I were a non resident in 2020?
It is really up to you. I don't see any downside for doing that but that may take some time.
4. why you said forget about tie breaker rules?
Your case is NOT that material/complicated to seek relief from Tax Treaty.
5. yes I disposed my residental property in HK in 2023 which was my principal residence until moving to Canada and since then my parents lived there until the disposal (rent free)... weighting up if i should report it in T1135 or as personal-use property.
You need an appraisal of your HK property on the day you think you became a tax resident. I think it was the day you landed. (I could be wrong) and compare the price on that day to the final selling price minus all expenses related to the disposal (commission, repairs etc.). I don't have enough information to determine if your HK property can be considered your Principal resident that could qualify for the exemption. However, you must report the disposition in either case. If you don't have a gain (price on day you landed vs final price on disposal) then, there will not be any tax issues. You may ended up with a net capital loss.
6. any recomondations for tax accountant in GTA?
My wife but she no longer takes new clients.