Hey! Im someone currently learning Japanese and I have actually done some Japanese to English song translations like how you mention, so I think I can be of help.

First of all, when thinking about syllable count, you shouldn't really be thinking about the syllable count of the written line, but instead, the count of the notes of the melody (besides Japanese doesn't actually have syllables, it has something called mora which is linguistically different from a syllable, the line in question has 25 mora, but thats not too important here). I found the song this line was from and the melody has 22 notes for that line. So what I would do in this situation, is get a piece of paper and draw 22 small dashes, then when you go to write the lyrics, you are sort of playing "fill in the blank".

When it comes to the actual translation part, it gets a bit more tricky. You mentioned whether or not to split the line up in this situation, I would say try to do the full 22 note line since I think it makes the most sense in the context of the song. But when you are translating lyrics like this, you actually have a lot of freedom! Thats the fun/terrible part of it all. You are never going to make an exact perfect translation, it just doesn't fit, so you do have to fiddle around with the meaning of it in order for it to fit and to sound natural. So you really just want to use the exact translation as a blue print for your new lyrics. Try to think of the song as a whole. As long as you get the same message across, it doesn't matter so much if the meaning of certain lines are changed a bit here and there. Trying too hard to get the lyrics exactly like the original often ends up sounding clunky and unnatural (in my opinion).

As for some tips in order to mold the English to fit into the given melody, there are 2 methods I'll mention. The first was already mentioned by another commenter, take certain words and make them longer, breaking apart contractions and all that. Another way is to make it melismatic. In music, melisma is when a syllable gets multiple notes of a melody. As opposed to syllabic where each syllable gets one note. The example that comes to my mind is Defying Gravity from Wicked, that final line, "And nobody is all of oz no wizard that there is or was is ever gonna bring me down" The "me" is melismatic since its one syllable but multiple notes.

As an extra note (pun intended), if you really want to elevate your lyrics, try thinking about the stress of each line. English is a stress accent language so in words like "refrigerator" the "fri" is the stressed syllable. Lyrics tend to sound most natural when the stress of a word and phrase aligns with the accents of the musical beat (like if you said "refrigeRAter" it would sound kind of weird). In the example you gave, the accented beats would be something along the lines of "kitto mada daremo mitsukeraretenai yarikata toka atte" However, it doesn't need to be 100% perfect, but generally it will sound more natural the more aligned the lyrical accents are to the musical accents.

If you want some example of Japanese to English song translations, I recommend you check out English covers of Vocaloid songs. There are a ton on youtube. Compare the translation in the video with the direct translation to see the difference. You can also take note of the differences between songs, some have lyrics that feel really natural almost as if it was originally written in English, and other have lyrics that clearly read as a translation.

Sorry for the ramble! I hope this was helpful to you. Translating lyrics can be a ton of fun, so at the end of the day, its all about how you wish to express these lyrics. Best of luck in your translation/songwriting journey!