Sitting on ~$800k USD cash from a windfall. Convert to CAD at ~1.42 now, or keep it in USD and invest there?

This ~$800k USD is windfall cash parked in PSU.U (USD T-bill ETF) yielding ~3.55% net. ~$280k USD of it is earmarked for a CAD tax bill next April.

USD/CAD is ~1.42, near a 1-year high (loonie weak). I need to deploy this cash into equities regardless... the open question is currency:

1. Convert USD→CAD now (Norbert's) and buy CAD-listed (XEQT, etc.), or
2. Keep it in USD and buy US-listed (VTI, etc.), accepting I'm structurally long USD?

I can also throw the $280k into a 9-month GIC for taxes at like 4.5%, but it'll be stuck in USD and exposed to all that drift.

I know ticker currency ≠ underlying exposure, but I keep circling. We don't earn much USD anymore after this windfall, but spend and will retire in CAD. What would you do at these levels? and would you DCA the conversion the same way you'd DCA the buy?