Sorry - but I do sympathise with you - and I can't suggest a way round this.
My last RC Parish had 2 large trees every year at the back of the Sanctuary - they were donated by the same family every year and yes , got bigger and more gaudy every year - flashing lights and all.
Eventually we pointed out to the Priest in charge that the flashing lights
could be a trigger for epileptic seizures so the lights no longer flashed [ that took 3 years

] However we could not stop the trees going up before mid-advent [ they went up originally on December 1 !! ]
Sorry - I suspect you are just going to have to grin and bear it / them .