Maybe go ahead and apply if its absolutely imperative you take that flight in April? We're almost at the end of January. February is a short month. April 20 will creep up soon... and if you are certain, you need to account for the time it takes for the passport journey too (approx. 1-1.5 months).
Me, personally also in a similar dilemma though I do not have a certain date or deadline for my PA to travel just yet. Late March would be optimum.
Here's my situation and thought process that I previously shared incase anyone missed it:
My PA is also hoping to come (move) to Canada in late March subject to spousal PR approval ofcourse... However, we have not made any concrete bookings or plans just yet. We have decided to put the plan to apply for a TRV on hold for maybe another week or two because we do feel a spousal application update is just around the corner. September 2025 applicant, we are awaiting BGC and the subsequent FD/PPR - it can happen anytime now (or hopefully by mid-February based on similar trends). I have heard that the passport visa stamping does take between 4-6 weeks after submission, meaning we may be looking at atleast a month for the passport to come back, so need to account for that time as well, regardless its a spousal PPR or a TRV PPR.