Turbo Tax 2021 for Mac question

I have NO interest in moving my 2015 MacBook Pro from Mojave 10.14 to whatever the latest and greatest is. I have already looked into so many of my current programs (including Parallels that runs an old version of Windows XP for me), my financial management software, and a myriad of other special programs I use for the film industry, that I risk not working anymore and having to re-buy new versions of all of those programs if I change OS from Mojave on my MAC.  This would be extremely costly when currently all of those other programs are working fantastic. I have no need to buy them again if I stick with Mojave.  

I've seen the alerts that TT says for this tax year we have to upgrade our OS since MAC won't support Mojave after Nov 2021. Does that for sure mean TT won't install once they send it to me? Or we just can't get support for it?  Obviously I also don't like the idea of not being able to use TT as I've used it every year for over 10 years. But I also have no interest in ruining a perfectly working computer with all its programs just for Turbo Tax either.  Every year this kind of 'alert' comes up, I hate it. I worry things won't work. But this time I know they likely won't survive the "Move" to a new OS b/c of the switch over from 32 bit to 64 bit between Mojave and whichever version was next and based on my research into at least 6 of my programs saying once I get off Mojave, I have to buy the programs again in order to use them. Even if just the upgrade price, it adds up to a huge expense adding all of them together. 

Any thoughts? What are other people in my boat doing about it? I can't just use TT online b/c we have small businesses on 1099s / single member LLCs.