Lacerte Tax Planner is included for free.  But a couple caveats.

I'm having issues rolling over tax *plans* from 2019 to 2020.  PY data sometimes gets deleted. I haven't cared enough to spend an hour on hold to ask Intuit to look into it.  So heads up, your issue may be served better by downloading the 2019 Tax Planner if you want to export the 2019 return as a base for your 2020 plan.

Also, I think in the planner that QBI-eligible income has to be separately input (whereas in Lacerte it's usually just an [O] field). Not sure about every screen, but just a heads up to watch for that since you said you need accuracy specifically in that arena.

Kind of as a summary to the above, Lacerte Tax Planner is a decent tool, but it's the redhead stepchild (IMO) of Lacerte. For all the effort (or lack thereof) Intuit puts into Lacerte coding cleanup, notably less is in the Planner. So maintain professional skepticism of your bottom line results (math errors happen), challenge assumptions, etc.

Good luck!