Ní dóigh liom gur cheart an "t-" a chur roimh "am" tar éis réamhfhocail agus an ailt.

Go deo 's lastall den am agus den spás.
Go deo 's thar an am agus thar an spás.
???

I wonder if repeating the preposition is necessary here as "time and space" are virtually a unit?

The OP should know 's, agus (and is) can be used interchangebly.

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(SL)(GM)

Beyond time and space like before and after death, what is outside of mortal time and space

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__̴ı̴̴̡̡̡ ̡͌l̡̡̡ ̡͌l̡*̡̡ ̴̡ı̴̴̡ ̡̡͡|̲̲̲͡͡͡ ̲▫̲͡ ̲̲̲͡͡π̲̲͡͡ ̲̲͡▫̲̲͡͡ ̲|̡̡̡ ̡ ̴̡ı̴̡̡ ̡͌l̡̡̡̡.___

Hey, that's a good point! There is nothing "beyond" the space-time continuum.

Yes there is, it's called Love.

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The dialect I use is Cork Irish.
Ar sgáth a chéile a mhairid na daoine, lag agus láidir, uasal is íseal

You're killing me, a Loin Dhuibh!