Hikari

Loved you to (topic), light (obj) — verbless: '(I give) light (to you)'. The verb is implied (probably 贈る or 捧げる).

Verbless gift-giving lines (X に Y を) are very common in Japanese songs and poems — leave the verb out, let the listener fill in the act of giving. The song's title 光 itself becomes the offering.

Faintly illuminate (te), goodbye, twice-and cannot-meet but — 二度と with a negative verb means 'never again'.

二度と〜ない is one of the heaviest finality phrases in Japanese: 二度と会えない (we'll never meet again), 二度と来ない (it'll never come back), 二度と忘れない (I'll never forget). The 二度 ('two times') is the lower bound being denied.

Where at be-(te) even, alright — question-word + 〜ても means 'no matter where/who/when/etc.'

どこにいても is the canonical phrase for 'wherever you are' — used in farewell speeches, graduation cards, parental texts to children moving abroad. The implication is unconditional reassurance.

Search-(stem) to let-go (Q) — volitional + か turns 'let's go' into 'shall we go?', a softer invitation.

Volitional + か is an idiomatic soft proposal: more inviting than 行こう alone, less direct than 行きますか. Reads like 'thinking aloud together'.

Flower (vocative-yo), bloom (te-form, soft command) — directly addressing flowers as if they could hear.

花よ咲いて is a stock J-pop image — addressing flowers, asking them to bloom on cue. Cherry-blossom country has a deep-set cultural impulse to talk to flowers as fellow living things.

Now (topic) sad-even-if, tomorrow (topic) surely alright — 〜くても is the i-adjective concessive form.

今は悲しくても明日はきっと大丈夫 — almost copy-paste from Japanese cards, condolences, and graduation speeches. ReoNa's J-pop hits often distill these soothing phrases into chorus lines.

Pain's heat-haze (subj) fly-go — 飛んでゆく is the literary spelling of 飛んでいく; ゆく is the older variant of 行く used in song lyrics for elegance.

陽炎 (kagerou) is the wavering heat-haze rising from sun-baked pavement — also the name of a famous WWII destroyer and a vocaloid song. It's a uniquely Japanese visual: present, but flickering and unreal.

Time's flow (subj) push-flow because — 押し流す = 押す (push) + 流す (let flow), forming a compound 'push (something) into the flow / wash away with force'.

押し流す is the hydrology word — used for floodwater carrying houses away. Used metaphorically for time washing away pain, it's stronger than just 流す: time doesn't merely cleanse, it forcibly removes.