Daichifr

Hi there, I'm brand new to the RX8 community and I am having an awesome time researching through this site and getting all the help needed!
I know this question was asked a lot and I'm not a brainless enough to not look through the previous threads about similar questions, but there was no clear answer!
So currently, my 2009 RX8 R3 has semi-synthetic 5W30 oil in it from the previous owner and Mazda recommends the 5W30 oil.
However, a lot of websites and people here recommends the 10W40 oil for North America(I live in Vancouver Canada) such as websites like:http://www.essexrotaryspecialists.com/technical/oil/, but on this website the conventional oil type is recommended where on threads like this: https://www.rx8club.com/series-i-tec...her-one-73807/, the person named rotarygod claims that synthetic is the best use.
I do own a full synthetic 5W30 for my BMW and the semi-synthetic 5W30 from the previous owner.
So my question is do I go out to buy 10W40 oil like this:https://www.canadiantire.ca/en/pdp/c...9206p.html#srp and change it? Also what type of oil do I use between conventional, semi-synthetic and synthetic?
And I saw that synthetic and conventional can be mixed in this thread: https://www.rx8club.com/new-member-f...4/#post4533706, so if I do decide to change it to 10W40, is it okay to just pour the oil in during the next oil change? (Obviously after draining the old 5W30 that was in the car)
I am sorry if I'm asking a stupid question, but there are too many varieties in the answer that I don't know which one I'm supposed to use and am super confused!
So any help would be much appreciated and thank you very much.