quarantine 'em

Now here's the thing. I'm not a historian, so this is second-hand, but from what I understand this IS deliberate obfuscation by the Church

Making Easter difficult to compute makes you reliant on the Church's calculations to know when your feast days should be celebrated

And once you can convert any Gregorian date to/from a lunar date (i.e. a position in that cycle) (also very doable), Computus becomes simple

Easter falls on the first Sunday following the "Paschal full Moon".

The "Paschal full Moon" is the first ecclesiastical full Moon on or after the ecclesiastical Northern Hemisphere spring equinox.

Neither the ecclesiastical full Moon nor the ecclesiastical Northern Hemisphere spring equinox are derived from astronomical observations...

If they were derived from astronomical observations, this would all be a lot easier!