Hi OnlyMe.

The maths ABSTRACTIONS and calculations which are used are useful, sure, but so were the EPICYCLES, remember? The point at this stage is to actually identify the REALITY POV, not the arbitrary abstract mathematical POV and interpretations, however useful they have been to date.

OnlyMe, everyone, Please Consider:

When currently it is interpreted that the 'spacetime' length contracts, it is a convenient reciproxal view ONLY. Becaue it is the 'time' part of that abstract math construct that is actually affected by SR-motion/GR-acceleration in-frame LOCAL (not abstract unreal co-ordinate view) REAL FORCES/PROCESSES.

So instead of just going along still with that 'spacetime' contraction which implies incorrectly that the 'space' component is 'contracting', why not just go for the obvious reality as per SR-motion/GR-acceleration effects predicted to affect the CLOCK 'time' component of that 'spacetime' construct....

and just admit that the abstract 'spacetime' contraction is actually the REAL 'time' rate contraction OF the tick rate of the clock used in the in-frame 'measurement when calculating the ACTUAL light speed IN that frame based on the IN-frame CLOCK 'time' variation to the 'standard second' which WOULD HAVE applied IF the NEW in-frame SR-motional/GR-accelerational conditions had been the same as the standard second definition frame from which the standard was taken.
Hence whence the 'invariant c' is derived with the proportional offset of the 'clock time' and the lightsped, and NOT any 'space' length contraction needed at all.

OnlyMe, everyone, please do NOT conflate/confuse this REAL 'invariant c' proportionate resultant quantity for the in-frame measure speed of light in every frame, due to compensating 'time' values used therein, with the purely mathematical equations TERM of 'constant c'. They are two different things!
Cheers, OnlyMe, at least I know you actually READ and try to understand properly, unlike some trolls and kneejerkers I could mention. Kudos to you, mate!