As the other answers affirm, the DeepL text is a word-for-word translation whereas Homze's text more effectively captures the essence of the original, rendering the human being's work a more effective translation. These answers give a good cultural accounting of why that is; i.e., why an English speaker would understand the certainty of the action in question, given full context.
I would like to explain why a German speaker would have no doubt about the sentence's meaning, and why it is grammatically correct to translate it into a less-ambiguous English form. Specifically, let's answer
Is it possible the Homze simply mistranslated from the original source...?
No. The sentence "So konnten noch [...] zum Einsatz gebracht werden" means unambiguously that something was definitively made use of in the past, because konnten is the simple past tense of können, and können with this spelling has no other meaning than the literal ability to do something.
The problem arises because German and English handle the subjunctive aspect in fundamentally different ways, to the extent that English speakers barely recognise the subjunctive mood at all -- even though we use it all the time. From Wikipedia:
Subjunctive forms of verbs are typically used to express various states of unreality such as: wish, emotion, possibility, judgment, opinion, obligation, or action that has not yet occurred; the precise situations in which they are used vary from language to language.
In particular, the English word could serves double-duty as both the simple past tense of can and as a marker for the subjunctive mood. Crucially, when used subjunctively, could is in the present tense.
Contrast "I can do that" with "I could do that" -- the former is an assertion of fact, and usually an offer to take direct action, while the latter is less concrete and more likely to be an opinion, a boast, or a weaker offer of assistance at some future point.
In order to express the subjunctive could in the past tense, we use the auxiliary verb have. "I could have done that" is a subjunctive statement about the past.
So we have a situation where "I could do X" means either "I was definitely able to do X [and did]" or "I am capable of doing X [but might not]", depending on whether it's the past tense of "can" or the present subjunctive marker. Which it is hinges on the overall context, the intentions of the speaker, and the understanding of the listener.
In German, this grammatical ambiguity simply does not exist. When German speakers wish to indicate the subjunctive mood, we use a whole class of verb forms called Konjunktiv II (technically, the second conjunctive declension). In practice, this means we usually use the verbs würden or wären or könnten (the KII forms of werden, sein, and können, respectively) as auxiliaries.
Thus if a German speaker reads "So konnten...gebracht werden", they understand immediately and intuitively that this is the literal past tense of können. If the writer had wished to express the subjunctive mood, they would have written "So könnten...gebracht werden".
tl;dr: DeepL"knows" that konnten is the past tense of können, and it "knows" that können is the cognate of can, and it further "knows" that could is (among other things) the past tense of can, but it doesn't (yet?) "know" the vagaries of the English subjunctive, and so it (mis-)translated the unambiguous German sentence into a much more ambiguous one in English.