You need to forget about this "light is a wave" for a moment because it's not relevant as photosynthesis is quantum-driven (
@Rocket Soul is spot on!). To correctly measure light intensity for our purposes we use PPFD or PPF or YPF but lux/lumen is irrelevant and grossly misleading. Any surplus energy of a photon <680nm or <700nm is dispersed as (mostly) heat.
A photon is the gauge-boson of the electro-magnetic force that is timeless, has always the impulse of c, and either -1 or +1 spin meaning there can be an infinite amount of photons at any given point in timespace, though if a critical energy-density is overstepped then they will recombine into an electron-positron pair which swiftly mutually annihiliates one another (they spin in opposite directions but meet after half), sending 2 photons away into diametral directions. This is actually what happens right in the center of the sun and the reason, since this process is slow, why the light from its core takes many many years to reach the sun's surface, and briefly after, us.
Any usage of lumen or lux or else is really only misleading, though the radiant flux of a fixture can give another hint at the quality of the lightsource together with its PPF. As blue light or UVA uses more energy up to be generated and is crucially needed for both photochemistry or bud quality. Some modern LED fixtures claim +3.5umols but are mostly 660nm mostly designed for greenhouse amendment light where there is already sufficient of blue and green from the sun. The same fixtures (e.g. that watercooled which got mentioned previously) then show 2.8umols/J in its whitelight-configuration.
I'm not really sure if that's Snakedope's LED light is true to its claim of 2.8umols, it looks like a faildesign with closed (from above) heatsinks and black colour so as to encapture light and release back as IR. BUT, if 2.8umols/W is true then he is actually blasting his plants with more than double the photon-count as previously released by his HPS (1.5umols/W) - HPS-900PPF vs LED-2184PPF LMAO all the while making matters worse by trying to reduce warmth which will only further reduce enzymatic activity and just slow photosynthesis down, potentially leading to higher buildup of dangerous triplett excitation states inside the light-harvesting complexes causing singulett oxygen which can damage DNA, proteins essentially bleaching leaves from the inside out. That needs to be repaired plus there will be a much higher loss of carbon from respiration. You need to buy yourself a quantum meter and measure PPFD at canopy level, then use an IR gun to take leaf surface temps then adjust your environment to align with a proper VPD & DLI. There's charts. And not be so ignorant, deflective when others ask you rhetorical questions with the intent to point you into the right direction and forget about all your self-styled wisdom derived from druged logic theory. That's not science, just do a clean slate and discard all that into the trashcan.
About photons, "how far it can reach" - well, infinitely. It will never stop flying which is the reason why we can observe extremely distant objects like quasars/blazars or the cosmic background radiation which is old as about 300.000years after the Big Bang - so 13.7billion years. They fly, fly, fly just the electromagnetic field gets less dense with distance, except for when a laser is being emitted.
One of the reasons why this quanta-wave-duality is in existance is due to the Uncertainty Principle that means we cannot absolutely true pinpoint the location AND time of a quantum particle, its either we either miss the time or the location slightly and that is due to the inane error imposed by our methods of observation (we use quantum particles like electrons but mostly photons), which additionally influence the nature of what we want to observe experimentally. The most famous experiment to show this is the Doppelspalt-experiment but still, we can quantify the number of particles in or out, in a discrete fashion, giving a true number and also recombine its energy equivalency to a 100% true number. There's nothing mysterious about it it's just 2 sides of the same coin.